+ifdef NO_LUA
+ LUA_MESSAGE := linking without specified Lua support
+ CGIT_CFLAGS += -DNO_LUA
+else
+ifeq ($(LUA_PKGCONFIG),)
+ LUA_PKGCONFIG := $(shell for pc in luajit lua lua5.2 lua5.1; do \
+ pkg-config --exists $$pc 2>/dev/null && echo $$pc && break; \
+ done)
+ LUA_MODE := autodetected
+else
+ LUA_MODE := specified
+endif
+ifneq ($(LUA_PKGCONFIG),)
+ LUA_MESSAGE := linking with $(LUA_MODE) $(LUA_PKGCONFIG)
+ LUA_LIBS := $(shell pkg-config --libs $(LUA_PKGCONFIG) 2>/dev/null)
+ LUA_CFLAGS := $(shell pkg-config --cflags $(LUA_PKGCONFIG) 2>/dev/null)
+ CGIT_LIBS += $(LUA_LIBS)
+ CGIT_CFLAGS += $(LUA_CFLAGS)
+else
+ LUA_MESSAGE := linking without autodetected Lua support
+ NO_LUA := YesPlease
+ CGIT_CFLAGS += -DNO_LUA
+endif
+
+endif
+
+# Add -ldl to linker flags on non-BSD systems.
+ifeq ($(findstring BSD,$(uname_S)),)
+ CGIT_LIBS += -ldl
+endif
+
+# glibc 2.1+ offers sendfile which the most common C library on Linux
+ifeq ($(uname_S),Linux)
+ HAVE_LINUX_SENDFILE = YesPlease
+endif
+
+ifdef HAVE_LINUX_SENDFILE
+ CGIT_CFLAGS += -DHAVE_LINUX_SENDFILE
+endif
+