Append -msgxx-glibc to TUNE_CCARGS for x86 PRO tools only

Lite toolchains don't include support for native libraries and thus
-msgxx-glibc is not a valid option. Added a check to see if the tools contain
a license directory to determine whether a pro (true) or lite (false)
toolchain is being used and set TUNE_CCARGS_append_x86 accordingly.

Tested with both Lite and pro toolchains.

Signed-off-by: Michael Powell <michael_powell@mentor.com>

conf/distro/include/tcmode-external-sourcery.inc

@@ -48,11 +48,6 @@ ENABLE_BINARY_LOCALE_GENERATION = ""
 
 TOOLCHAIN_OPTIONS = " --sysroot=${STAGING_DIR_HOST}"
 
-# These bits are here temporarily to sidestep the need to use a separate set
-# of tune files to pass the appropriate multilib selection arguments to the
-# sourcery toolchain, as is needed to extract the sysroot content.
-TUNE_CCARGS_append_x86 = " -msgxx-glibc"
-
 # Unfortunately, the CSL ia32 toolchain has non-prefixed binaries in its
 # bindir (e.g. gcc, ld). To avoid this messing up our build, we avoid adding
 # this bindir to our PATH, and instead add symlinks to the prefixed binaries
@@ -81,6 +76,10 @@ python toolchain_metadata_setup () {
     if os.path.exists(bb.data.expand('${EXTERNAL_TOOLCHAIN}/bin/gcc', l)):
         d.setVar('TOOLCHAIN_PATH_ADD', '')
 
+    if os.path.exists(bb.data.expand('${EXTERNAL_TOOLCHAIN}/license', l)):
+        # Assuming use of a CodeBench Pro toolchain
+        d.setVar('TUNE_CCARGS_append_x86', " -msgxx-glibc")
+
     # The external toolchain may not have been built with the yocto preferred
     # gnu hash setting, so ensure that the corresponding sanity check is a
     # warning, not an error.