populate_base_sdk: Stop running gcc --version all the time

Running 'gcc --version' for every image recipe is slow and increases parsing
time/resource usage for no good reason. Only compute the value in when we're
really running the task/function.

(From OE-Core rev: bf49316bb9913b7c89de64d6a194be31aa66e16b)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/populate_sdk_base.bbclass

@@ -259,7 +259,7 @@ EOF
 		-e 's#@SDK_VERSION@#${SDK_VERSION}#g' \
 		-e '/@SDK_PRE_INSTALL_COMMAND@/d' \
 		-e '/@SDK_POST_INSTALL_COMMAND@/d' \
-		-e 's#@SDK_GCC_VER@#${@oe.utils.host_gcc_version(d)}#g' \
+		-e 's#@SDK_GCC_VER@#${@oe.utils.host_gcc_version(d, taskcontextonly=True)}#g' \
 		${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.sh
 
 	# add execution permission

meta/lib/oe/utils.py

@@ -342,9 +342,12 @@ def format_pkg_list(pkg_dict, ret_format=None):
 
     return '\n'.join(output)
 
-def host_gcc_version(d):
+def host_gcc_version(d, taskcontextonly=False):
     import re, subprocess
 
+    if taskcontextonly and d.getVar('BB_WORKERCONTEXT') != '1':
+        return
+
     compiler = d.getVar("BUILD_CC")
     try:
         env = os.environ.copy()