[PATCH] bpfilter: check if $(CC) can static link in Kconfig

[Masahiro Yamada]

On Fedora, linking static libraries requires the glibc-static RPM
package, which is not part of the glibc-devel package.

CONFIG_CC_CAN_LINK does not check the capability of static linking,
so you can enable CONFIG_BPFILTER_UMH, then fail to build.

  HOSTLD  net/bpfilter/bpfilter_umh
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status

Add CONFIG_CC_CAN_LINK_STATIC, and make CONFIG_BPFILTER_UMH depend
on it.

Reported-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

I will insert this after
https://patchwork.kernel.org/patch/11515997/

 init/Kconfig         | 5 +++++
 net/bpfilter/Kconfig | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 57562a8e2761..d0ff16e93794 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -49,6 +49,11 @@ config CC_CAN_LINK
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m64-flag)) if 64BIT
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m32-flag))
 
+config CC_CAN_LINK_STATIC
+	bool
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m64-flag)) if 64BIT
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m32-flag))
+
 config CC_HAS_ASM_GOTO
 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
 
diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
index fed9290e3b41..045144d4a42c 100644
--- a/net/bpfilter/Kconfig
+++ b/net/bpfilter/Kconfig
@@ -9,7 +9,7 @@ menuconfig BPFILTER
 if BPFILTER
 config BPFILTER_UMH
 	tristate "bpfilter kernel module with user mode helper"
-	depends on CC_CAN_LINK
+	depends on CC_CAN_LINK_STATIC
 	default m
 	help
 	  This builds bpfilter kernel module with embedded user mode helper
-- 
2.25.1