CPPFLAGS="$CPPFLAGS -coverage -Wall -fprofile-arcs"
In a vanilla gnu make, there's no such thing as CCFLAGS. There are CFLAGS, CPPFLAGS, and CXXFLAGS. CFLAGS for the C compiler, CXXFLAGS for C++, and CPPFLAGS for both.
php-ext coverage .m4
CPPFLAGS="$CPPFLAGS -coverage -Wall -fprofile-arcs"
EXTRA_LDFLAGS="$EXTRA_LDFLAGS -precious-files-regex '.*(gcda|gcno)'"