cmake: restore parallel build support for bootstrap

Signed-off-by: Felix Fietkau <nbd@nbd.name>

tools/cmake/Makefile

@@ -20,7 +20,9 @@ HOST_CONFIGURE_PARALLEL:=1
 include $(INCLUDE_DIR)/host-build.mk
 
 HOST_CONFIGURE_CMD := \
-	MAKEFLAGS="$(HOST_JOBS)" $(BASH) ./configure
+	MAKEFLAGS="$(HOST_JOBS)" \
+	$(BASH) ./configure \
+		$(if $(MAKE_JOBSERVER),--parallel="$(MAKE_JOBSERVER)")
 
 HOST_CONFIGURE_VARS :=
 

tools/cmake/patches/150-bootstrap_parallel_make_flag.patch

@@ -0,0 +1,14 @@
+--- a/bootstrap
++++ b/bootstrap
+@@ -958,7 +958,10 @@ int main(){ printf("1%c", (char)0x0a); r
+ ' > "test.c"
+ cmake_original_make_flags="${cmake_make_flags}"
+ if [ "x${cmake_parallel_make}" != "x" ]; then
+-  cmake_make_flags="${cmake_make_flags} -j ${cmake_parallel_make}"
++  case "$cmake_paralle_make" in
++    [0-9]*) cmake_parallel_make="-j ${cmake_parallel_make}";;
++  esac
++  cmake_make_flags="${cmake_make_flags} ${cmake_parallel_make}"
+ fi
+ for a in ${cmake_make_processors}; do
+   if [ -z "${cmake_make_processor}" ] && cmake_try_make "${a}" "${cmake_make_flags}" >> ../cmake_bootstrap.log 2>&1; then