erts: Fix depend target in pcre.mk

Rename it to not be invoked during OTP build.

Author: sverker

erts/emulator/pcre/README.pcre_update.md

@@ -305,7 +305,7 @@ pcre.mk after all testing is done.
 
 Regenerate the make dependencies in `depend.mk` with:
 
-    ~/erts/emulator/pcre/> make -f pcre.mk depend
+    ~/erts/emulator/pcre/> make -f pcre.mk static_depend
 
 Now your pcre.mk is fairly up to date and it's time to start patching in the changes...
 

erts/emulator/pcre/pcre.mk

@@ -86,7 +86,12 @@ $(PCRE_YIELD_COV): $(PCRE_DIR)/pcre2_match.c
 	done > $@; \
 	echo "#define ERLANG_YIELD_POINT_CNT $$INDEX" >> $@
 
-depend:
+
+# Target static_depend is currently only ment to be run manually.
+# It works on Ubuntu Linux but not en FreeBSD for example.
+# > make -f pcre.mk static_depend
+# > git add depend.mk
+static_depend:
 	gcc -MM -MG -c -DERLANG_INTEGRATION -DDEBUG *.c \
 		| sed -E 's/\S+\.o:/$$(PCRE_OBJDIR)\/&/' \
 		| sed -E 's/\S+\.[ch]\b/$$(PCRE_DIR)\/&/g' > depend.mk