Link libpq with libdl if the platform needs that.

Since b0635bfda, libpq uses dlopen() and related functions.  On some
platforms these are not supplied by libc, but by a separate library
libdl, in which case we need to make sure that that dependency is
known to the linker.  Meson seems to take care of that automatically,
but the Makefile didn't cater for it.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1328170.1752082586@sss.pgh.pa.us
Backpatch-through: 18

diff --git a/src/interfaces/libpq/Makefile b/src/interfaces/libpq/Makefile
index 853aab4b1b886e60496693cde03ce3158e379d73..47d67811509441d5ef0f4cc14ff05b92aefcf28b 100644 (file)
--- a/src/interfaces/libpq/Makefile
+++ b/src/interfaces/libpq/Makefile
@@ -87,7 +87,7 @@ endif
 # that are built correctly for use in a shlib.
 SHLIB_LINK_INTERNAL = -lpgcommon_shlib -lpgport_shlib
 ifneq ($(PORTNAME), win32)
-SHLIB_LINK += $(filter -lcrypt -ldes -lcom_err -lcrypto -lk5crypto -lkrb5 -lgssapi_krb5 -lgss -lgssapi -lssl -lsocket -lnsl -lresolv -lintl -lm, $(LIBS)) $(LDAP_LIBS_FE) $(PTHREAD_LIBS)
+SHLIB_LINK += $(filter -lcrypt -ldes -lcom_err -lcrypto -lk5crypto -lkrb5 -lgssapi_krb5 -lgss -lgssapi -lssl -lsocket -lnsl -lresolv -lintl -ldl -lm, $(LIBS)) $(LDAP_LIBS_FE) $(PTHREAD_LIBS)
 else
 SHLIB_LINK += $(filter -lcrypt -ldes -lcom_err -lcrypto -lk5crypto -lkrb5 -lgssapi32 -lssl -lsocket -lnsl -lresolv -lintl -lm $(PTHREAD_LIBS), $(LIBS)) $(LDAP_LIBS_FE)
 endif