Fix filtering of INI directives to respect leading whitespaces

Directives are now correctly filtered out if the line in the php.ini
file begins with whitespace characters.

Closes phpGH-19348

Author: madmajestro

build/Makefile.global

@@ -90,7 +90,7 @@ PHP_TEST_SHARED_EXTENSIONS =  ` \
 			. $$i; $(top_srcdir)/build/shtool echo -n -- " -d zend_extension=$(top_builddir)/modules/$$dlname"; \
 		done; \
 	fi`
-PHP_DEPRECATED_DIRECTIVES_REGEX = '^(magic_quotes_(gpc|runtime|sybase)?|(zend_)?extension(_debug)?(_ts)?)[\t\ ]*='
+PHP_DEPRECATED_DIRECTIVES_REGEX = '^[\t\ ]*(magic_quotes_(gpc|runtime|sybase)?|(zend_)?extension(_debug)?(_ts)?)[\t\ ]*='
 
 test: all
 	@if test ! -z "$(PHP_EXECUTABLE)" && test -x "$(PHP_EXECUTABLE)"; then \