configure: Use pg_config to locate the header location

Changelog-Fixed: build: On some operating systems the postgresql library would not get picked up. `./configure` now uses `pg_config` to locate the headers.

Makefile

@@ -205,7 +205,7 @@ BOLT_DEPS := $(BOLT_GEN)
 ALL_PROGRAMS =
 
 CPPFLAGS += -DBINTOPKGLIBEXECDIR="\"$(shell sh tools/rel.sh $(bindir) $(pkglibexecdir))\""
-CFLAGS = $(CPPFLAGS) $(CWARNFLAGS) $(CDEBUGFLAGS) $(COPTFLAGS) -I $(CCANDIR) $(EXTERNAL_INCLUDE_FLAGS) -I . -I/usr/local/include $(FEATURES) $(COVFLAGS) $(DEV_CFLAGS) -DSHACHAIN_BITS=48 -DJSMN_PARENT_LINKS $(PIE_CFLAGS) $(COMPAT_CFLAGS) -DBUILD_ELEMENTS=1
+CFLAGS = $(CPPFLAGS) $(CWARNFLAGS) $(CDEBUGFLAGS) $(COPTFLAGS) -I $(CCANDIR) $(EXTERNAL_INCLUDE_FLAGS) -I . -I/usr/local/include $(POSTGRES_INCLUDE) $(FEATURES) $(COVFLAGS) $(DEV_CFLAGS) -DSHACHAIN_BITS=48 -DJSMN_PARENT_LINKS $(PIE_CFLAGS) $(COMPAT_CFLAGS) -DBUILD_ELEMENTS=1
 # If CFLAGS is already set in the environment of make (to whatever value, it
 # does not matter) then it would export it to subprocesses with the above value
 # we set, including CWARNFLAGS which by default contains -Wall -Werror. This

configure

@@ -229,8 +229,14 @@ fi
 # Doesn't set a var, but makes sure it exists
 require 'python3-mako' "You need the mako module for python3: see doc/INSTALL.md" python3 -c 'import mako'
 
+POSTGRES_INCLUDE=""
+if command -v pg_config 2> /dev/null; then
+    POSTGRES_INCLUDE="-I$(pg_config --includedir)"
+fi
+
 rm -f $CONFIG_VAR_FILE.$$
-$CONFIGURATOR --extra-tests --autotools-style --var-file=$CONFIG_VAR_FILE.$$ --header-file=$CONFIG_HEADER --configurator-cc="$CONFIGURATOR_CC" --wrapper="$CONFIGURATOR_WRAPPER" "$CC" ${CWARNFLAGS-$BASE_WARNFLAGS} $CDEBUGFLAGS $COPTFLAGS -I/usr/local/include -L/usr/local/lib <<EOF
+$CONFIGURATOR --extra-tests --autotools-style --var-file=$CONFIG_VAR_FILE.$$ --header-file=$CONFIG_HEADER --configurator-cc="$CONFIGURATOR_CC" --wrapper="$CONFIGURATOR_WRAPPER" "$CC" ${CWARNFLAGS-$BASE_WARNFLAGS} $CDEBUGFLAGS $COPTFLAGS -I/usr/local/include -L/usr/local/lib $POSTGRES_INCLUDE <<EOF
+
 var=HAVE_GOOD_LIBSODIUM
 desc=libsodium with IETF chacha20 variants
 style=DEFINES_EVERYTHING|EXECUTE|MAY_NOT_COMPILE
@@ -286,7 +292,7 @@ desc=postgres
 style=DEFINES_EVERYTHING|EXECUTE|MAY_NOT_COMPILE
 link=-lpq
 code=
-#include <postgresql/libpq-fe.h>
+#include <libpq-fe.h>
 #include <stdio.h>
 
 int main(void)
@@ -353,6 +359,7 @@ add_var CONFIGURATOR_CC "$CONFIGURATOR_CC"
 add_var CWARNFLAGS "$CWARNFLAGS"
 add_var CDEBUGFLAGS "$CDEBUGFLAGS"
 add_var COPTFLAGS "$COPTFLAGS"
+add_var POSTGRES_INCLUDE "$POSTGRES_INCLUDE"
 add_var VALGRIND "$VALGRIND"
 add_var DEVELOPER "$DEVELOPER" $CONFIG_HEADER
 add_var EXPERIMENTAL_FEATURES "$EXPERIMENTAL_FEATURES" $CONFIG_HEADER

wallet/db_postgres.c

@@ -8,7 +8,7 @@
 
 #if HAVE_POSTGRES
 /* Indented in order not to trigger the inclusion order check */
-  #include <postgresql/libpq-fe.h>
+  #include <libpq-fe.h>
 
 /* Cherry-picked from here: libpq/src/interfaces/ecpg/ecpglib/pg_type.h */
 #define BYTEAOID		17