[openwrt/openwrt] tools/expat: fix compilation with ccache

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/b0650c50c8f040cf3f94af0f9b07e65c14f36045

commit b0650c50c8f040cf3f94af0f9b07e65c14f36045
Author: Rosen Penev <rosenp at gmail.com>
AuthorDate: Sun Jul 27 11:37:27 2025 -0700

    tools/expat: fix compilation with ccache
    
    Even though expat is a C library, the configure script tests both C and
    C++ compilers so a fix is needed for the latter.
    
    Signed-off-by: Rosen Penev <rosenp at gmail.com>
    Link: https://github.com/openwrt/openwrt/pull/19594
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 tools/expat/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/expat/Makefile b/tools/expat/Makefile
index 941f0c3fbf..8e46aa989e 100644
--- a/tools/expat/Makefile
+++ b/tools/expat/Makefile
@@ -20,6 +20,7 @@ HOST_BUILD_PARALLEL:=1
 include $(INCLUDE_DIR)/host-build.mk
 
 HOSTCC := $(HOSTCC_NOCACHE)
+HOSTCXX := $(HOSTCXX_NOCACHE)
 
 HOST_CONFIGURE_ARGS += \
 	--disable-shared \