oauth: Correct missing comma in Requires.private

I added libcurl to the Requires.private section of libpq.pc in commit
b0635bfda, but I missed that the Autoconf side needs commas added
explicitly. Configurations which used both --with-libcurl and
--with-openssl ended up with the following entry:

    Requires.private: libssl, libcrypto libcurl

The pkg-config parser appears to be fairly lenient in this case, and
accepts the whitespace as an equivalent separator, but let's not rely on
that. Add an add_to_list macro (inspired by Makefile.global's
add_to_path) to build up the PKG_CONFIG_REQUIRES_PRIVATE list correctly.

Reported-by: Wolfgang Walther <walther@technowledgy.de>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Discussion: https://postgr.es/m/CAOYmi+k2z7Rqj5xiWLUT0+bSXLvdE7TYgS5gCOSqSyXyTSSXiQ@mail.gmail.com

diff --git a/src/interfaces/libpq/Makefile b/src/interfaces/libpq/Makefile
index c6fe5fec7f64d299397bf379ef769bd36744744b..853aab4b1b886e60496693cde03ce3158e379d73 100644 (file)
--- a/src/interfaces/libpq/Makefile
+++ b/src/interfaces/libpq/Makefile
@@ -98,14 +98,21 @@ SHLIB_PREREQS = submake-libpgport
 
 SHLIB_EXPORTS = exports.txt
 
+# Appends to a comma-separated list.
+comma := ,
+define add_to_list
+$(eval $1 := $(if $($1),$($1)$(comma) $2,$2))
+endef
+
 ifeq ($(with_ssl),openssl)
-PKG_CONFIG_REQUIRES_PRIVATE = libssl, libcrypto
+$(call add_to_list,PKG_CONFIG_REQUIRES_PRIVATE,libssl)
+$(call add_to_list,PKG_CONFIG_REQUIRES_PRIVATE,libcrypto)
 endif
 
 ifeq ($(with_libcurl),yes)
 # libpq.so doesn't link against libcurl, but libpq.a needs libpq-oauth, and
 # libpq-oauth needs libcurl. Put both into *.private.
-PKG_CONFIG_REQUIRES_PRIVATE += libcurl
+$(call add_to_list,PKG_CONFIG_REQUIRES_PRIVATE,libcurl)
 %.pc: override SHLIB_LINK_INTERNAL += -lpq-oauth
 endif