cargo build --target armv7-linux-androideabi --release throws an error when building Holochain for Android.

[dlee67]

I am trying to build Holochain for Android with my chosen target by following the link below:

https://github.com/holochain/holochain-rust/blob/develop/doc/holochain_101/src/building_for_android.md

but I have a blockage, where error is asking if I have "arm-linux-androideabi-clang" installed.

The below is the log I am getting:

Updating crates.io index
    Updating git repository `https://github.com/ddd-mtl/wabt-rs.git`                                                                                  
  Downloaded synstructure v0.10.1                                                                                                                     
  Downloaded uuid v0.7.1                                                                                                                              
  Downloaded boolinator v2.4.0                                                                                                                        
  Downloaded objekt v0.1.1                                                                                                                            
  Downloaded regex-syntax v0.6.3                                                                                                                      
  Downloaded structopt v0.2.13                                                                                                                        
  Downloaded walkdir v2.2.7                                                                                                                           
  Downloaded structopt-derive v0.2.13                                                                                                                 
  Downloaded heck v0.3.0                                                                                                                              
  Downloaded unicode-segmentation v1.2.1                                                                                                              
   Compiling either v1.5.0                                                                                                                            
   Compiling num-traits v0.2.6                                                                                                                        
   Compiling version_check v0.1.5                                                                                                                     
   Compiling libc v0.2.43                                                                                                                             
   Compiling proc-macro2 v0.4.23                                                                                                                      
   Compiling num-integer v0.1.39                                                                                                                      
   Compiling typenum v1.10.0                                                                                                                          
   Compiling num-bigint v0.2.1                                                                                                                        
   Compiling pkg-config v0.3.14                                                                                                                       
   Compiling error-chain v0.10.0                                                                                                                      
   Compiling toml v0.2.1                                                                                                                              
   Compiling unicode-xid v0.1.0                                                                                                                       
   Compiling cfg-if v0.1.6                                                                                                                            
   Compiling serde v0.8.23                                                                                                                            
   Compiling num-rational v0.2.1                                                                                                                      
   Compiling lazy_static v1.2.0                                                                                                                       
   Compiling num-iter v0.1.37                                                                                                                         
   Compiling num-complex v0.2.1                                                                                                                       
   Compiling ucd-util v0.1.2                                                                                                                          
   Compiling regex v1.0.6                                                                                                                             
   Compiling cc v1.0.25                                                                                                                               
   Compiling serde v1.0.80                                                                                                                            
   Compiling ryu v0.2.7                                                                                                                               
   Compiling crunchy v0.1.6                                                                                                                           
   Compiling rand_core v0.3.0                                                                                                                         
   Compiling utf8-ranges v1.0.2                                                                                                                       
   Compiling byte-tools v0.2.0                                                                                                                        
   Compiling arrayref v0.3.5                                                                                                                          
   Compiling regex v0.2.11                                                                                                                            
   Compiling fake-simd v0.1.2                                                                                                                         
   Compiling itoa v0.4.3                                                                                                                              
   Compiling failure_derive v0.1.3                                                                                                                    
   Compiling indexmap v1.0.2                                                                                                                          
   Compiling linked-hash-map v0.5.1                                                                                                                   
   Compiling lazy_static v0.2.11                                                                                                                      
   Compiling byteorder v1.2.7                                                                                                                         
   Compiling sha1 v0.5.0                                                                                                                              
   Compiling rustc-demangle v0.1.9                                                                                                                    
   Compiling futures v0.1.25                                                                                                                          
   Compiling objekt v0.1.1                                                                                                                            
   Compiling snowflake v1.3.0                                                                                                                         
   Compiling bitflags v1.0.4                                                                                                                          
   Compiling runtime-fmt v0.3.0                                                                                                                       
   Compiling num-derive v0.2.3                                                                                                                        
   Compiling safemem v0.3.0                                                                                                                           
   Compiling same-file v1.0.4                                                                                                                         
   Compiling memory_units v0.3.0                                                                                                                      
   Compiling unicode-width v0.1.5                                                                                                                     
   Compiling unwrap_to v0.1.0                                                                                                                         
   Compiling unicode-segmentation v1.2.1                                                                                                              
   Compiling nan-preserving-float v0.1.0                                                                                                              
   Compiling strsim v0.7.0                                                                                                                            
   Compiling vec_map v0.8.1                                                                                                                           
   Compiling ansi_term v0.11.0                                                                                                                        
   Compiling remove_dir_all v0.5.1                                                                                                                    
   Compiling boolinator v2.4.0                                                                                                                        
   Compiling futures-core-preview v0.2.3                                                                                                              
   Compiling iovec v0.1.2                                                                                                                             
   Compiling num_cpus v1.8.0                                                                                                                          
   Compiling memchr v1.0.2                                                                                                                            
   Compiling time v0.1.40                                                                                                                             
   Compiling rand v0.4.3                                                                                                                              
   Compiling atty v0.2.11                                                                                                                             
   Compiling directories v1.0.2                                                                                                                       
   Compiling memchr v2.1.1                                                                                                                            
   Compiling log v0.4.6                                                                                                                               
   Compiling thread_local v0.3.6                                                                                                                      
   Compiling regex-syntax v0.6.3                                                                                                                      
   Compiling regex-syntax v0.5.6                                                                                                                      
   Compiling metadeps v1.1.2                                                                                                                          
   Compiling serde_test v0.8.23                                                                                                                       
   Compiling rand_core v0.2.2                                                                                                                         
   Compiling block-buffer v0.3.3                                                                                                                      
   Compiling yaml-rust v0.4.2                                                                                                                         
   Compiling backtrace-sys v0.1.24                                                                                                                    
   Compiling parity-wasm v0.31.3                                                                                                                      
   Compiling base64 v0.9.3                                                                                                                            
   Compiling walkdir v2.2.7                                                                                                                           
   Compiling textwrap v0.10.0                                                                                                                         
   Compiling heck v0.3.0                                                                                                                              
   Compiling futures-channel-preview v0.2.2                                                                                                           
   Compiling futures-io-preview v0.2.2                                                                                                                
   Compiling bytes v0.4.10                                                                                                                            
   Compiling futures-cpupool v0.1.8                                                                                                                   
   Compiling nom v3.2.1                                                                                                                               
   Compiling uuid v0.6.5                                                                                                                              
   Compiling log v0.3.9                                                                                                                               
   Compiling linked-hash-map v0.3.0                                                                                                                   
   Compiling zmq-sys v0.8.2                                                                                                                           
   Compiling rand v0.5.5                                                                                                                              
error: failed to run custom build command for `backtrace-sys v0.1.24`                                                                                 
process didn't exit successfully: `/home/bob/Desktop/WorkSpace/holochain-rust/target/release/build/backtrace-sys-8c8f78174dc2aab6/build-script-build` (exit code: 101)
--- stdout
TARGET = Some("armv7-linux-androideabi")
OPT_LEVEL = Some("3")
HOST = Some("x86_64-unknown-linux-gnu")
CC_armv7-linux-androideabi = None
CC_armv7_linux_androideabi = None
TARGET_CC = None
CC = None
CFLAGS_armv7-linux-androideabi = None
CFLAGS_armv7_linux_androideabi = None
TARGET_CFLAGS = None
CFLAGS = None
DEBUG = Some("false")
running: "arm-linux-androideabi-clang" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=armv7-linux-androideabi" "-I" "src/libbacktrace" "-I" "/home/bob/Desktop/WorkSpace/holochain-rust/target/armv7-linux-androideabi/release/build/backtrace-sys-2ef8c1ee024444e7/out" "-fvisibility=hidden" "-DBACKTRACE_ELF_SIZE=32" "-DBACKTRACE_SUPPORTED=1" "-DBACKTRACE_USES_MALLOC=1" "-DBACKTRACE_SUPPORTS_THREADS=0" "-DBACKTRACE_SUPPORTS_DATA=0" "-D_GNU_SOURCE=1" "-D_LARGE_FILES=1" "-Dbacktrace_full=__rbt_backtrace_full" "-Dbacktrace_dwarf_add=__rbt_backtrace_dwarf_add" "-Dbacktrace_initialize=__rbt_backtrace_initialize" "-Dbacktrace_pcinfo=__rbt_backtrace_pcinfo" "-Dbacktrace_syminfo=__rbt_backtrace_syminfo" "-Dbacktrace_get_view=__rbt_backtrace_get_view" "-Dbacktrace_release_view=__rbt_backtrace_release_view" "-Dbacktrace_alloc=__rbt_backtrace_alloc" "-Dbacktrace_free=__rbt_backtrace_free" "-Dbacktrace_vector_finish=__rbt_backtrace_vector_finish" "-Dbacktrace_vector_grow=__rbt_backtrace_vector_grow" "-Dbacktrace_vector_release=__rbt_backtrace_vector_release" "-Dbacktrace_close=__rbt_backtrace_close" "-Dbacktrace_open=__rbt_backtrace_open" "-Dbacktrace_print=__rbt_backtrace_print" "-Dbacktrace_simple=__rbt_backtrace_simple" "-Dbacktrace_qsort=__rbt_backtrace_qsort" "-Dbacktrace_create_state=__rbt_backtrace_create_state" "-Dbacktrace_uncompress_zdebug=__rbt_backtrace_uncompress_zdebug" "-o" "/home/bob/Desktop/WorkSpace/holochain-rust/target/armv7-linux-androideabi/release/build/backtrace-sys-2ef8c1ee024444e7/out/src/libbacktrace/alloc.o" "-c" "src/libbacktrace/alloc.c"

--- stderr
thread 'main' panicked at '

Internal error occurred: Failed to find tool. Is `arm-linux-androideabi-clang` installed?

', /home/bob/.cargo/registry/src/github.com-1ecc6299db9ec823/cc-1.0.25/src/lib.rs:2260:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.

warning: build failed, waiting for other jobs to finish...
error: build failed                

Soon as I got the error above, I went to check if I got all the dependencies.
The below is ls output from NDK/arm/bin.

2to3                             arm-linux-androideabi-ld       clang             ld.lld           llvm-symbolizer   python2-config
arm-linux-androideabi-addr2line  arm-linux-androideabi-ld.bfd   clang++           llvm-ar          make              python-config
arm-linux-androideabi-ar         arm-linux-androideabi-ld.gold  clang70           llvm-as          ndk-depends       python-config.sh
arm-linux-androideabi-as         arm-linux-androideabi-nm       clang70++         llvm-cov         ndk-gdb           sancov
arm-linux-androideabi-c++filt    arm-linux-androideabi-objcopy  clang-format      llvm-dis         ndk-gdb.py        sanstats
arm-linux-androideabi-clang      arm-linux-androideabi-objdump  clang-tidy        llvm-link        ndk-stack         scan-build
arm-linux-androideabi-clang++    arm-linux-androideabi-ranlib   clang-tidy.real   llvm-modextract  ndk-which         scan-view
arm-linux-androideabi-dwp        arm-linux-androideabi-readelf  gcore             llvm-nm          pydoc             smtpd.py
arm-linux-androideabi-elfedit    arm-linux-androideabi-size     gdb               llvm-objcopy     python            yasm
arm-linux-androideabi-g++        arm-linux-androideabi-strings  gdb-orig          llvm-profdata    python2
arm-linux-androideabi-gcc        arm-linux-androideabi-strip    git-clang-format  llvm-readobj     python2.7
arm-linux-androideabi-gprof      bisect_driver.py               idle              llvm-strip       python2.7-config

I've tried substituting the $NDK_HOME with the absolute paths for my toolchains in .cargo/config, where all targets are similar looking to:

/home/bob/Android/Sdk/ndk-bundle/NDK/arm/bin/arm-linux-androideabi-ar

but the error hasn't gone away..

Is there any way around this error?

Thank you!