Handle Python with non-default names

Check for python2/python3 and if found, pass them to --with-python.
Allow user to override the choice via a new config option. This
fixes systems where there is no "python", only "python2" or "python3".

Signed-off-by: Alexey Neyman <stilor@att.net>

config/debug/gdb.in.cross

@@ -50,6 +50,22 @@ config GDB_CROSS_PYTHON
       have been reports of problems when linking gdb to the static
       libpython.a. This should be fixed in gdb >=7.3. YMMV.
 
+config GDB_CROSS_PYTHON_BINARY
+    string "Python binary to use"
+    depends on GDB_CROSS_PYTHON
+    help
+      The path to a binary passed to GDB configure. You may need to
+      specify this if Python is not available under the default name
+      (i.e. 'python'). By default, crosstool-NG will try python, python3
+      and python2, in that order.
+
+      To use this option in a canadian/cross-native build, you will
+      need to provide a helper script that will report the compilation
+      and linking flags for the host's Python, since configure script
+      will not be able to run the interpreter and query it. See the
+      help message in gdb's configure script for the --with-python option
+      for further guidance.
+
 config GDB_CROSS_EXTRA_CONFIG_ARRAY
     string
     prompt "Cross-gdb extra config"

scripts/build/debug/300-gdb.sh

@@ -48,7 +48,7 @@ do_debug_gdb_build() {
 
     if [ "${CT_GDB_CROSS}" = "y" ]; then
         local -a cross_extra_config
-        local gcc_version
+        local gcc_version p _p
 
         CT_DoStep INFO "Installing cross-gdb"
         CT_DoLog EXTRA "Configuring cross-gdb"
@@ -75,7 +75,20 @@ do_debug_gdb_build() {
             *)      cross_extra_config+=("--enable-threads");;
         esac
         if [ "${CT_GDB_CROSS_PYTHON}" = "y" ]; then
-            cross_extra_config+=( "--with-python=yes" )
+            if [ -z "${CT_GDB_CROSS_PYTHON_BINARY}" ]; then
+                for p in python python3 python2; do
+                    _p=$( which "${p}" || true )
+                    if [ -n "${_p}" ]; then
+                       cross_extra_config+=( "--with-python=${_p}" )
+                       break
+                    fi
+                done
+                if [ -z "${_p}" ]; then
+                    CT_Abort "Python support requested in cross-gdb, but Python not found. Set CT_GDB_CROSS_PYTHON_BINARY in your config."
+                fi
+            else
+                cross_extra_config+=( "--with-python=${CT_GDB_CROSS_PYTHON_BINARY}" )
+            fi
         else
             cross_extra_config+=( "--with-python=no" )
         fi