cmake failures on Ubuntu 20.04

[gshimansky]

While executing cmake -DCMAKE_BUILD_TYPE=Release .. -DPYTHON_EXECUTABLE=/usr/bin/python3 on Ubuntu 20.04 I get the following errors:

-- The C compiler identification is GNU 9.3.0
-- The CXX compiler identification is GNU 9.3.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found PythonInterp: /usr/bin/python3 (found version "3.8.2")
-- detected CFLAGS for Python extensions: -fPIC
-- detected LDFLAGS for Python extensions: -Wl,-Bsymbolic-functions  -Wl,-z,relro -g -fwrapv -O2
-- libunwind needs lzma on this platform
-- Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython3.8.so (found version "3.8.2")
-- Configuring done
CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


CMake Error at /nfs/site/home/gashiman/work/pysamprof/common/CMakeLists.txt:33 (add_library):
  Target "pysamprof-common" links to item "-Wl,-Bsymbolic-functions
  -Wl,-z,relro -g -fwrapv -O2 " which has leading or trailing whitespace.
  This is now an error according to policy CMP0004.


-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.

The problem is in Python configuration files so I ended up editing /usr/lib/python3.8/_sysconfigdata__x86_64-linux-gnu.py and removing all whitespace after -O2 where I found this flag (I am not sure exactly which lines goes into cmake config). But I don't think this is a correct way of handling this problem. Here is an answer to a similar problem https://stackoverflow.com/a/51367125/4584975 explaining how to strip whitespace from cmake config variables. I think it should be added to CMakeLists.txt.