ruby: hack for yacc (fix build)

dev-lang/ruby/ruby-2.7.4.recipe

@@ -13,7 +13,7 @@ HOMEPAGE="https://www.ruby-lang.org/"
 COPYRIGHT="1993-2021 Yukihiro Matsumoto"
 LICENSE="Ruby
 	BSD (3-clause)"
-REVISION="1"
+REVISION="2"
 SOURCE_URI="https://cache.ruby-lang.org/pub/ruby/2.7/ruby-$portVersion.tar.bz2"
 CHECKSUM_SHA256="bffa8aec9da392eda98f1c561071bb6e71d217d541c617fc6e3282d79f4e7d48"
 SOURCE_DIR="ruby-$portVersion"
@@ -88,6 +88,16 @@ BUILD_PREREQUIRES="
 defineDebugInfoPackage ruby$secondaryArchSuffix \
 	"$libDir"/libruby.so.$libVersion
 
+PATCH()
+{
+	# Hack for ripper build
+	sed -i \
+		-e "/#define YYLTYPE_IS_DECLARED 1/a #define YYEMPTY -2" \
+		-e "/#define YYLTYPE_IS_DECLARED 1/a #define YYUNDEF 257" \
+		-e "/#define YYLTYPE_IS_DECLARED 1/a #define YYerror 256" \
+		$sourceDir/ext/ripper/ripper.y
+}
+
 BUILD()
 {
 	export CFLAGS="-D_BSD_SOURCE"