cmake: include/cmake.mk add CMAKE_BINARY_SUBDIR to allow out of source tree builds

Some packages need out of source tree building with cmake, for example
when building kernel modules.
See an example here:
https://sourceforge.net/p/accel-ppp/code/ci/master/tree/README

Signed-off-by: Luke McKee <hojuruku@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [cleanup, rework]

diff --git a/include/cmake.mk b/include/cmake.mk
index 009c6c27728e52eec7131952149232bfa7e60168..fac2bc0227b435a281123fe30f819e6efafc56ca 100644 (file)
--- a/include/cmake.mk
+++ b/include/cmake.mk
@@ -6,7 +6,9 @@ ifneq ($(findstring c,$(OPENWRT_VERBOSE)),)
   MAKE_FLAGS+=VERBOSE=1
 endif
 
-CMAKE_SOURCE_DIR:=.
+CMAKE_BINARY_DIR = $(PKG_BUILD_DIR)$(if $(CMAKE_BINARY_SUBDIR),/$(CMAKE_BINARY_SUBDIR))
+CMAKE_SOURCE_DIR = $(PKG_BUILD_DIR)
+MAKE_PATH = $(firstword $(CMAKE_BINARY_SUBDIR) .)
 
 ifeq ($(CONFIG_EXTERNAL_TOOLCHAIN),)
   cmake_tool=$(TOOLCHAIN_DIR)/bin/$(1)
@@ -35,7 +37,8 @@ CMAKE_HOST_FIND_ROOT_PATH:=$(STAGING_DIR)/host;$(STAGING_DIR_HOST)
 CMAKE_SHARED_LDFLAGS:=-Wl,-Bsymbolic-functions
 
 define Build/Configure/Default
-       (cd $(PKG_BUILD_DIR); \
+       mkdir -p $(CMAKE_BINARY_DIR)
+       (cd $(CMAKE_BINARY_DIR); \
                CFLAGS="$(TARGET_CFLAGS) $(EXTRA_CFLAGS)" \
                CXXFLAGS="$(TARGET_CFLAGS) $(EXTRA_CFLAGS)" \
                LDFLAGS="$(TARGET_LDFLAGS) $(EXTRA_LDFLAGS)" \

diff --git a/include/package-defaults.mk b/include/package-defaults.mk
index 2896b4c7830dcd1e146362f7cdb79afc9834d79c..e371c3bdff286d90aa1ce8a9bc6b95d68512aea4 100644 (file)
--- a/include/package-defaults.mk
+++ b/include/package-defaults.mk
@@ -136,7 +136,7 @@ MAKE_INSTALL_FLAGS = \
        $(MAKE_FLAGS) \
        DESTDIR="$(PKG_INSTALL_DIR)"
 
-MAKE_PATH = .
+MAKE_PATH ?= .
 
 define Build/Compile/Default
        +$(MAKE_VARS) \