Re: [PATCH 1/2] Makefile: use curl-config to determine curl flags

[Junio C Hamano <gitster@pobox.com>]

Dave Borowitz <dborowitz@google.com> writes:

> curl-config should always be installed alongside a curl distribution,
> and its purpose is to provide flags for building against libcurl, so
> use it instead of guessing flags and dependent libraries.
>
> Allow overriding CURL_CONFIG to a custom path to curl-config, to
> compile against a curl installation other than the first in PATH.
>
> Use this only when CURLDIR is not explicitly specified, to continue
> supporting older builds.
>
> Signed-off-by: Dave Borowitz <dborowitz@google.com>

Sounds logically the right thing to do.  Was there a particular
platform that needed this (i.e. cannot be made to work with the
existing CURLDIR and "guessing flags and dependeent libraries")
that may be worth mentioning in the log message?

> ---
>  Makefile | 35 +++++++++++++++++++++++------------
>  1 file changed, 23 insertions(+), 12 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 2128ce3..d6330bc 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -34,8 +34,12 @@ all::
>  # git-http-push are not built, and you cannot use http:// and https://
>  # transports (neither smart nor dumb).
>  #
> +# Define CURL_CONFIG to the path to a curl-config binary other than the
> +# default 'curl-config'.
> +#
>  # Define CURLDIR=/foo/bar if your curl header and library files are in
> -# /foo/bar/include and /foo/bar/lib directories.
> +# /foo/bar/include and /foo/bar/lib directories.  This overrides CURL_CONFIG,
> +# but is less robust.
>  #
>  # Define NO_EXPAT if you do not have expat installed.  git-http-push is
>  # not built, and you cannot push using http:// and https:// transports (dumb).
> @@ -143,9 +147,11 @@ all::
>  #
>  # Define NEEDS_SSL_WITH_CRYPTO if you need -lssl when using -lcrypto (Darwin).
>  #
> -# Define NEEDS_SSL_WITH_CURL if you need -lssl with -lcurl (Minix).
> +# Define NEEDS_SSL_WITH_CURL if you need -lssl with -lcurl (Minix).  Only used
> +# if CURLDIR is set.
>  #
> -# Define NEEDS_IDN_WITH_CURL if you need -lidn when using -lcurl (Minix).
> +# Define NEEDS_IDN_WITH_CURL if you need -lidn when using -lcurl (Minix).  Only
> +# used if CURLDIR is set.
>  #
>  # Define NEEDS_LIBICONV if linking with libc is not enough (Darwin).
>  #
> @@ -1121,18 +1127,23 @@ else
>  		# Try "-Wl,-rpath=$(CURLDIR)/$(lib)" in such a case.
>  		BASIC_CFLAGS += -I$(CURLDIR)/include
>  		CURL_LIBCURL = -L$(CURLDIR)/$(lib) $(CC_LD_DYNPATH)$(CURLDIR)/$(lib) -lcurl
> +		ifdef NEEDS_SSL_WITH_CURL
> +			CURL_LIBCURL += -lssl
> +			ifdef NEEDS_CRYPTO_WITH_SSL
> +				CURL_LIBCURL += -lcrypto
> +			endif
> +		endif
> +		ifdef NEEDS_IDN_WITH_CURL
> +			CURL_LIBCURL += -lidn
> +		endif
>  	else
> -		CURL_LIBCURL = -lcurl
> -	endif
> -	ifdef NEEDS_SSL_WITH_CURL
> -		CURL_LIBCURL += -lssl
> -		ifdef NEEDS_CRYPTO_WITH_SSL
> -			CURL_LIBCURL += -lcrypto
> +		CURL_CONFIG ?= curl-config
> +		BASIC_CFLAGS += $(shell $(CURL_CONFIG) --cflags)
> +		CURL_LIBCURL = $(shell $(CURL_CONFIG) --libs)
> +		ifeq "$(CURL_LIBCURL)" ""
> +			$(error curl not detected; try setting CURLDIR)
>  		endif
>  	endif
> -	ifdef NEEDS_IDN_WITH_CURL
> -		CURL_LIBCURL += -lidn
> -	endif
>  
>  	REMOTE_CURL_PRIMARY = git-remote-http$X
>  	REMOTE_CURL_ALIASES = git-remote-https$X git-remote-ftp$X git-remote-ftps$X