dev-scheme/guile: fix CFLAGS=-gddb3 build failure, bug#608190

guile-snarf uses cpp to get rid of comments, #defines
and type declarations in C code. But in -ggdb3 mode gcc
leaves all of them in the output.

The workaround is to downgrade -ggdb3 down to -ggdb2.

Bug: https://bugs.gentoo.org/608190

Package-Manager: Portage-2.3.3, Repoman-2.3.1

dev-scheme/guile/guile-2.0.14.ebuild

@@ -42,6 +42,9 @@ src_configure() {
 	# see bug #178499
 	filter-flags -ftree-vectorize
 
+	# see bug #608190
+	replace-flags -ggdb[3-9] -ggdb2
+
 	econf \
 		--disable-error-on-warning \
 		--disable-rpath \