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>
(cherry picked from commit 0a9a52ee77)

admin/syslog-ng/Makefile

@@ -16,11 +16,17 @@ PKG_HASH:=092bd17fd47002c988aebdf81d0ed3f3cfd0e82b388d2453bcaa5e67934f4dda
 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
@@ -97,6 +103,7 @@ 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