annotate all mocked functions with noinline

CLang's optimizer is more aggressive at inlining functions than
gcc and so will often inline functions that our tests want to
mock-override. This causes the test to fail in bizarre ways.

We don't want to disable inlining completely, but we must at
least prevent inlining of mocked functions. Fortunately there
is a 'noinline' attribute that lets us control this per function.

A syntax check rule is added that parses tests/*mock.c to extract
the list of functions that are mocked (restricted to names starting
with 'vir' prefix). It then checks that src/*.h header file to
ensure it has a 'ATTRIBUTE_NOINLINE' annotation. This should prevent
use from bit-rotting in future.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

cfg.mk

@@ -1069,7 +1069,7 @@ _autogen:
 # regenerate HACKING as part of the syntax-check
 ifneq ($(_gl-Makefile),)
 syntax-check: $(top_srcdir)/HACKING spacing-check test-wrap-argv \
-	prohibit-duplicate-header
+	prohibit-duplicate-header mock-noinline
 endif
 
 # Don't include duplicate header in the source (either *.c or *.h)
@@ -1083,6 +1083,10 @@ spacing-check:
 	  { echo '$(ME): incorrect formatting, see HACKING for rules' 1>&2; \
 	    exit 1; }
 
+mock-noinline:
+	$(AM_V_GEN)files=`$(VC_LIST) | grep '\.[ch]$$'`; \
+	$(PERL) $(top_srcdir)/build-aux/mock-noinline.pl $$files
+
 test-wrap-argv:
 	$(AM_V_GEN)files=`$(VC_LIST) | grep -E '\.(ldargs|args)'`; \
 	$(PERL) $(top_srcdir)/tests/test-wrap-argv.pl --check $$files