Variables are defined in buildroot/package/Makefile.in

• $(TARGET_CC) - cross compiler gcc binary (i.e.: TARGET_CC=/home/user/project/out/host/usr/bin/ccache /home/user/project/out/host/usr/bin/arm-linux-gcc)
• $(TARGET_AR) $(TARGET_AS) $(TARGET_CPP) $(TARGET_CXX) _FC _LD _NM _RANLIB _READELF _OBJCOPY _OBJDUMP
• $(TARGET_CC_NOCCACHE)
• $(TARGET_CXX_NOCCACHE)

• $(TARGET_CFLAGS) - (i.e: TARGET_CFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -Os -g2)
• $(TARGEt_CPPFLAGS)
• $(TARGET_CXXFLAGS)
• $(TARGET_LDFLAGS)

• $(TARGET_MAKE_ENV) - env which has to be set for cross compilation. It overrides search path, to get cross compiler first. (i.e:PATH=“/home/user/project/out/host/bin:/home/user/project/out/host/ …)
• $(TARGET_DIR) - device root filesystem (i.e: needed for installing packages into $(TARGET_DIR)/usr/bin)
• $(STAGING_DIR) - development target root filesystem (contains all needed libraries to build other packages, contains debug info and not stripped binary)

Additional variables (not needed in normal use)

• $(CCACHE) - full path to ccache binary or empty (i.e: CCACHE=/home/user/project/out/host/usr/bin/ccache)
• $(TARGET_CROSS) - prefix with full path to cross compiler (i.e: TARGET_CROSS=/home/user/project/out/host/usr/bin/arm-linux-)
• $(ABI) - gnueabi[hf] | eabi[hf]

CC=“$(TARGET_CC) $(TARGET_CFLAGS)