syslog-ng: fix build on macos

configure script detects Darwin and uses flags incompatible with
Linux target build.

This patch uses fakeuname tool if host OS is MacOS to avoid Darwin
detection on target build.

Signed-off-by: Sergey V. Lobanov <sergey@lobanov.in>

admin/syslog-ng/Makefile

@@ -16,11 +16,17 @@ PKG_HASH:=1d0238b06b3e5987c859e5b529ecee738f75bacff04b149398b1fe8cbb121e53
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1
 
+PKG_BUILD_DEPENDS:= \
+	HOST_OS_MACOS:fakeuname/host \
+
 PKG_CONFIG_DEPENDS:= \
 	CONFIG_IPV6 \
 
 include $(INCLUDE_DIR)/package.mk
 include $(INCLUDE_DIR)/nls.mk
+ifeq ($(CONFIG_HOST_OS_MACOS),y)
+    include ../../utils/fakeuname/fakeuname.mk
+endif
 
 define Package/syslog-ng
   SECTION:=admin
@@ -69,6 +75,7 @@ CONFIGURE_ARGS +=  \
 	--with-mongoc=no
 
 CONFIGURE_VARS += \
+	$(if $(CONFIG_HOST_OS_MACOS),PATH=$(FAKEUNAME_PATH):$(PATH)) \
 	LIBDBI_CFLAGS="-I$(STAGING_DIR)/usr/include"
 
 define Package/syslog-ng/install