Makefile

#
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###
### This file is just a very small wrapper needed to run the real make/Init.gmk.
### It also performs some sanity checks on make.
###

# The shell code below will be executed on /usr/bin/make on Solaris, but not in GNU Make.
# /usr/bin/make lacks basically every other flow control mechanism.
.TEST_FOR_NON_GNUMAKE:sh=echo You are not using GNU Make/gmake, this is a requirement. Check your path. 1>&2 && exit 1

# The .FEATURES variable is likely to be unique for GNU Make.
ifeq ($(.FEATURES), )
  $(info Error: '$(MAKE)' does not seem to be GNU Make, which is a requirement.)
  $(info Check your path, or upgrade to GNU Make 3.81 or newer.)
  $(error Cannot continue)
endif

# Assume we have GNU Make, but check version.
ifeq ($(strip $(foreach v, 3.81% 3.82% 4.%, $(filter $v, $(MAKE_VERSION)))), )
  $(info Error: This version of GNU Make is too low ($(MAKE_VERSION)).)
  $(info Check your path, or upgrade to GNU Make 3.81 or newer.)
  $(error Cannot continue)
endif

# In Cygwin, the MAKE variable gets prepended with the current directory if the
# make executable is called using a Windows mixed path (c:/cygwin/bin/make.exe).
ifneq ($(findstring :, $(MAKE)), )
  MAKE := $(patsubst $(CURDIR)%, %, $(patsubst $(CURDIR)/%, %, $(MAKE)))
endif

# Locate this Makefile
ifeq ($(filter /%, $(lastword $(MAKEFILE_LIST))),)
  makefile_path := $(CURDIR)/$(strip $(lastword $(MAKEFILE_LIST)))
else
  makefile_path := $(lastword $(MAKEFILE_LIST))
endif
topdir := $(strip $(patsubst %/, %, $(dir $(makefile_path))))

# ... and then we can include the real makefile
include $(topdir)/make/Init.gmk