build: Build pipe-loader before gallium tests

And don't build it from other Makefiles. That's awful, and breaks
distclean.

Tested-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-and-Tested-by: Andreas Boll <andreas.boll.dev@gmail.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

configure.ac

@@ -1397,10 +1397,6 @@ if test "x$enable_opencl" = xyes; then
 fi
 AM_CONDITIONAL(HAVE_CLOVER, test "x$enable_opencl" = xyes)
 
-if test "x$enable_gallium_gbm" = xyes || test "x$enable_opencl" = xyes; then
-    GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS pipe-loader"
-fi
-
 dnl
 dnl Gallium configuration
 dnl
@@ -1666,6 +1662,10 @@ if test "x$enable_gallium_tests" = xyes; then
 fi
 AM_CONDITIONAL(HAVE_GALLIUM_TESTS, test "x$enable_gallium_tests" = xyes)
 
+if test "x$enable_gallium_loader" = xyes; then
+    GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS pipe-loader"
+fi
+
 dnl Directory for VDPAU libs
 AC_ARG_WITH([vdpau-libdir],
     [AS_HELP_STRING([--with-vdpau-libdir=DIR],