Add crt* since some symbols are required by lang/php/7.3+

Index: libgcc/config/rs6000/t-openbsd
--- libgcc/config/rs6000/t-openbsd.orig
+++ libgcc/config/rs6000/t-openbsd
@@ -0,0 +1,12 @@
+# already added in libgcc/config/rs6000/t-ppccomm
+# LIB2ADD = $(srcdir)/config/rs6000/tramp.S
+
+LIB2ADD_ST += \
+	$(srcdir)/config/rs6000/crtsavfpr.S \
+	$(srcdir)/config/rs6000/crtresfpr.S \
+	$(srcdir)/config/rs6000/crtsavgpr.S \
+	$(srcdir)/config/rs6000/crtresgpr.S \
+	$(srcdir)/config/rs6000/crtresxfpr.S \
+	$(srcdir)/config/rs6000/crtresxgpr.S \
+	$(srcdir)/config/rs6000/crtsavevr.S \
+	$(srcdir)/config/rs6000/crtrestvr.S