Use DOTNET_${$1} environment variables

Commit migrated from https://github.com/dotnet/coreclr/commit/89dcb477d1fd1e772c8ce1558e103ee72af60c3b

diff --git a/src/coreclr/src/pal/tools/gen-buildsys-gcc.sh b/src/coreclr/src/pal/tools/gen-buildsys-gcc.sh
index 9cee893..7aba64c 100755 (executable)
--- a/src/coreclr/src/pal/tools/gen-buildsys-gcc.sh
+++ b/src/coreclr/src/pal/tools/gen-buildsys-gcc.sh
@@ -9,8 +9,8 @@ then
   echo "gen-buildsys-gcc.sh <path to top level CMakeLists.txt> <GccMajorVersion> <GccMinorVersion> <Architecture> [build flavor] [coverage] [ninja] [cmakeargs]"
   echo "Specify the path to the top level CMake file - <ProjectK>/src/NDP"
   echo "Specify the Gcc version to use, split into major and minor version"
-  echo "Specify the target architecture." 
-  echo "Optionally specify the build configuration (flavor.) Defaults to DEBUG." 
+  echo "Specify the target architecture."
+  echo "Optionally specify the build configuration (flavor.) Defaults to DEBUG."
   echo "Optionally specify 'coverage' to enable code coverage build."
   echo "Target ninja instead of make. ninja must be on the PATH."
   echo "Pass additional arguments to CMake call."
@@ -45,15 +45,21 @@ else
     exit 1
 fi
 
-if [ -z "$CC" ]; then
+if [ -z "$DOTNET_CC" ]; then
     CC="$(command -v "${gcc_prefix}"gcc"$desired_gcc_version")"
     export CC
+else
+    CC="$DOTNET_CC"
 fi
-if [ -z "$CXX" ]; then
+
+if [ -z "$DOTNET_CXX" ]; then
     CXX="$(command -v "${gcc_prefix}g++$desired_gcc_version")"
-    export CXX
+else
+    CXX="$DOTNET_CXX"
 fi
 
+export CC CXX
+
 build_arch="$4"
 buildtype=DEBUG
 code_coverage=OFF
@@ -85,6 +91,12 @@ done
 OS=$(uname)
 
 locate_gcc_exec() {
+  ENV_KNOB="DOTNET_$(echo "$1" | tr '[:lower:]' '[:upper:]')"
+  if [ -n $(eval "\$$ENV_KNOB") ]; then
+    $(eval "\$$ENV_KNOB")
+    return
+  fi
+
   if command -v "$gcc_prefix$1$desired_gcc_version" > /dev/null 2>&1
   then
     command -v "$gcc_prefix$1$desired_gcc_version"