fix(callgrind/tests): use -fno-builtin-printf to prevent printf inlining

Replace -D_FORTIFY_SOURCE=0 with -fno-builtin-printf to prevent the
compiler from treating printf as a builtin function that can be inlined.
This ensures the inline tests only capture the intended inline function
calls without printf appearing in the callgrind output.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: art049

callgrind/tests/Makefile.am

@@ -34,8 +34,8 @@ AM_CFLAGS   += $(AM_FLAG_M3264_PRI)
 AM_CXXFLAGS += $(AM_FLAG_M3264_PRI)
 
 # Inline tests need -O2 to enable inlining and -g for debug info
-# Use -D_FORTIFY_SOURCE=0 to prevent glibc from inlining printf and other stdio functions
-inline_samefile_CFLAGS = $(AM_CFLAGS) -O2 -g -D_FORTIFY_SOURCE=0
-inline_crossfile_CFLAGS = $(AM_CFLAGS) -O2 -g -D_FORTIFY_SOURCE=0
+# Use -fno-builtin-printf to prevent compiler from inlining printf
+inline_samefile_CFLAGS = $(AM_CFLAGS) -O2 -g -fno-builtin-printf
+inline_crossfile_CFLAGS = $(AM_CFLAGS) -O2 -g -fno-builtin-printf
 
 threads_LDADD = -lpthread