zabbix.proxy-{pgsql,mysql}: Fix cross

pkgs/servers/monitoring/zabbix/proxy.nix

@@ -8,6 +8,7 @@
   openssl,
   pcre,
   zlib,
+  buildPackages,
   odbcSupport ? true,
   unixODBC,
   snmpSupport ? stdenv.buildPlatform == stdenv.hostPlatform,
@@ -29,6 +30,23 @@ assert sqliteSupport -> !mysqlSupport && !postgresqlSupport;
 
 let
   inherit (lib) optional optionalString;
+
+  fake_pg_config = buildPackages.writeShellScript "pg_config" ''
+    if [[ "$1" == "--version" ]]; then
+      $PKG_CONFIG libpq --modversion
+    else
+      $PKG_CONFIG libpq --variable="''${1//--/}"
+    fi
+  '';
+
+  fake_mysql_config = buildPackages.writeShellScript "mysql_config" ''
+    if [[ "$1" == "--version" ]]; then
+      $PKG_CONFIG mysqlclient --modversion
+    else
+      $PKG_CONFIG mysqlclient $@
+    fi
+  '';
+
 in
 import ./versions.nix (
   { version, hash, ... }:
@@ -71,8 +89,8 @@ import ./versions.nix (
       ++ optional snmpSupport "--with-net-snmp"
       ++ optional sqliteSupport "--with-sqlite3=${sqlite.dev}"
       ++ optional sshSupport "--with-ssh2=${libssh2.dev}"
-      ++ optional mysqlSupport "--with-mysql"
-      ++ optional postgresqlSupport "--with-postgresql";
+      ++ optional mysqlSupport "--with-mysql=${fake_mysql_config}"
+      ++ optional postgresqlSupport "--with-postgresql=${fake_pg_config}";
 
     prePatch = ''
       find database -name data.sql -exec sed -i 's|/usr/bin/||g' {} +