[source] build: ensure PKG_INFO_DIR exists before trying to use it

[LEDE Commits]

jogo pushed a commit to source.git, branch master:
https://git.lede-project.org/e5e5c3f5fd38f1f0dd8d4672fc64bdd0a1a01add

commit e5e5c3f5fd38f1f0dd8d4672fc64bdd0a1a01add
Author: Jonas Gorski <jonas.gorski at gmail.com>
AuthorDate: Sat Oct 28 11:19:25 2017 +0200

    build: ensure PKG_INFO_DIR exists before trying to use it
    
    PKG_INFO_DIR is only created at the finish step of the first package
    build, but kernel modules now use it at the start. Doing a parallel build
    could cause a kernel module to be the first package, breaking the build.
    
    Fix this by ensuring the directory exists.
    
    Fixes: 2e496876c60c ("kernel: collect module symvers for external modules")
    Signed-off-by: Jonas Gorski <jonas.gorski at gmail.com>
---
 include/kernel.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/kernel.mk b/include/kernel.mk
index f2099ad..f2d2a12 100644
--- a/include/kernel.mk
+++ b/include/kernel.mk
@@ -133,6 +133,7 @@ define populate_module_symvers
 endef
 
 define collect_module_symvers
+	@mkdir -p $(PKG_INFO_DIR)
 	for subdir in $(PKG_EXTMOD_SUBDIRS); do \
 		grep -F $(PKG_BUILD_DIR) $(PKG_BUILD_DIR)/$$$$subdir/Module.symvers >> $(PKG_BUILD_DIR)/Module.symvers.tmp; \
 	done; \