Allow running make in subdirs again.

Makefile

@@ -42,6 +42,7 @@ DATA_FILES := $(wildcard $(SRC_PATH)/ffpresets/*.ffpreset)
 
 SKIPHEADERS = cmdutils_common_opts.h
 
+MAIN_MAKEFILE=1
 include common.mak
 
 FF_LDFLAGS   := $(FFLDFLAGS)

common.mak

@@ -7,6 +7,12 @@ all: all-yes
 
 ifndef SUBDIR
 
+ifndef MAIN_MAKEFILE
+ifeq ($(SRC_PATH),.)
+SRC_PATH = ..
+endif
+endif
+
 ifndef V
 Q      = @
 ECHO   = printf "$(1)\t%s\n" $(2)