On 14/02/2019 23:34, Luc Van Oostenryck wrote: > From: Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> > > Debian build scripts pass CFLAGS in the environment. > However, this is ignored by Sparse's Makefile since 'CFLAGS' > is unconditionaly initialized. > > Fix this by initializing CFLAGS to their default value using '?='. > Do the same for PKG_CONFIG, CHECKER, CHECKER_FLAGS and > DESTDIR, BINDIR, MANDIR & MAN1DIR. > > Note: It's useless to try to do the same for CC, LD & AR since > they're builtin variables so '?= ...' is a no-op for them > (unless make is called with -R). BTW, I have seen (a long time ago) an ugly hack to try and get around this 'special behaviour' of the variables from make's built-in database. It is very ugly, ... Suppose you wanted to set 'CC ?= gcc' in the Makefile, but because CC is 'special', you don't get the 'use the value from the environment if set, else default to this value'. An ugly workaround would look something like this: $ git diff diff --git a/Makefile b/Makefile index 025bce2..a98a9fc 100644 --- a/Makefile +++ b/Makefile @@ -4,8 +4,9 @@ VERSION=0.6.0 # The following variables can be overwritten from the command line OS = linux - +ifeq ($(origin CC),default) CC = gcc +endif CFLAGS = -O2 -g CFLAGS += -Wall -Wwrite-strings LD = $(CC) @@ -20,6 +21,9 @@ BINDIR=$(PREFIX)/bin MANDIR=$(PREFIX)/share/man MAN1DIR=$(MANDIR)/man1 +fred: + @echo "CC is $(CC), origin: " $(origin CC) + # Allow users to override build settings without dirtying their trees # For debugging, put this in local.mk: # $ $ make fred Makefile:128: Your system does not have libxml, disabling c2xml Makefile:150: Your system does not have gtk3/gtk2, disabling test-inspect Makefile:183: Your system does not have llvm, disabling sparse-llvm CC is gcc, origin: file $ $ make CC=cmd fred make: cmd: Command not found Makefile:128: Your system does not have libxml, disabling c2xml Makefile:150: Your system does not have gtk3/gtk2, disabling test-inspect Makefile:183: Your system does not have llvm, disabling sparse-llvm CC is cmd, origin: command line $ $ CC=env make fred env: unrecognised option '--print-file-name=' Try 'env --help' for more information. Makefile:128: Your system does not have libxml, disabling c2xml Makefile:150: Your system does not have gtk3/gtk2, disabling test-inspect Makefile:183: Your system does not have llvm, disabling sparse-llvm CC is env, origin: environment $ [Note: the 'make: cmd: Command not found' and similar message about the 'env' invocation comes from the '$(shell $(CC) ...)' further down the makefile (see line 100, setting GCC_BASE).] Hmm, it may be possible to create a define ... :-P ATB, Ramsay Jones
