tools: fix v8 testing with devtoolset on ppcle

The devtoolset doesn't use or set the CXX, etc, env vars, so ignore them
if not present.

PR-URL: #28458
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

tools/make-v8.sh

@@ -12,7 +12,9 @@ if [[ "$ARCH" == "s390x" ]] || [[ "$ARCH" == "ppc64le" ]]; then
   export BUILD_TOOLS=/home/iojs/build-tools
   export LD_LIBRARY_PATH=$BUILD_TOOLS:$LD_LIBRARY_PATH
   export PATH=$BUILD_TOOLS:$PATH
-  CXX_PATH=`which $CXX |grep g++`
+  if [[ X"$CXX" != X ]]; then
+    CXX_PATH=`which $CXX |grep g++`
+  fi
   rm -f "$BUILD_TOOLS/g++"
   rm -f "$BUILD_TOOLS/gcc"
 fi
@@ -24,8 +26,10 @@ if [[ "$ARCH" == "s390x" ]]; then
   gn gen -v out.gn/$BUILD_ARCH_TYPE --args='is_component_build=false is_debug=false use_goma=false goma_dir="None" use_custom_libcxx=false v8_target_cpu="s390x" target_cpu="s390x"'
   ninja -v -C out.gn/$BUILD_ARCH_TYPE d8 cctest inspector-test
 elif [[ "$ARCH" == "ppc64le" ]]; then
-  ln -s /usr/bin/$CXX "$BUILD_TOOLS/g++"
-  ln -s /usr/bin/$CC "$BUILD_TOOLS/gcc"
+  if [[ X"$CXX" != X ]]; then
+    ln -s /usr/bin/$CXX "$BUILD_TOOLS/g++"
+    ln -s /usr/bin/$CC "$BUILD_TOOLS/gcc"
+  fi
   g++ --version
   export PKG_CONFIG_PATH=$BUILD_TOOLS/pkg-config-files
   gn gen out.gn/$BUILD_ARCH_TYPE --args='is_component_build=false is_debug=false use_goma=false goma_dir="None" use_custom_libcxx=false v8_target_cpu="ppc64" target_cpu="ppc64"'