[Buildroot] [git commit branch/2020.02.x] package/exim: fix build with ccache

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=a28d658ecb7c5686130bb02e2f1c921b2bf93b09
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2020.02.x

When using ccache to build the exim package, the HOSTCC value contains
spaces, that are incorrectly interpreted by exim's Makefilei, which uses
the first word of ${CC} to test compiler options. This breaks the build
with "unrecognized option" ccache errors.

Fix that by wrapping the HOSTCC variable in double quotes, as it is done
for other variables that follow.

Signed-off-by: Alejandro González <alejandro.gonzalez.correo at gmail.com>
[yann.morin.1998 at free.fr: slight rewording of commit log]
Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
(cherry picked from commit a9486e337ac7b32a58c31618a070c1b9f9ca9506)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/exim/exim.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package/exim/exim.mk b/package/exim/exim.mk
index dc445c6d93..90ec364168 100644
--- a/package/exim/exim.mk
+++ b/package/exim/exim.mk
@@ -123,8 +123,8 @@ endif
 define EXIM_BUILD_CMDS
 	$(TARGET_MAKE_ENV) build=br $(MAKE) -C $(@D) makefile
 	$(HOST_MAKE_ENV) $(MAKE) -C $(@D)/build-br macro_predef \
-		CC=$(HOSTCC) \
-		LNCC=$(HOSTCC) \
+		CC="$(HOSTCC)" \
+		LNCC="$(HOSTCC)" \
 		CFLAGS="-std=c99 $(HOST_CFLAGS)" \
 		LFLAGS="-fPIC $(HOST_LDFLAGS)"
 	$(TARGET_MAKE_ENV) build=br $(MAKE) -C $(@D) $(EXIM_STATIC_FLAGS) \