DOC: Improve the message printed when running `make` w/o `TARGET`

Rephrase the message to no longer talk about something that "is no longer
supported", but about what actually *is* supported.

Adjustments include:

- Removal of rare targets to make it easier to find the proper one.
- Reformatting to be easier to read (more newlines)
- Explanation of common non-default feature flags.

diff --git a/Makefile b/Makefile
index 0ea3ef6..4e6c834 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -790,23 +790,35 @@ endif
 
 ifeq ($(TARGET),)
 all:
+       @echo "Building HAProxy without specifying a TARGET is not supported."
        @echo
-       @echo "Due to too many reports of suboptimized setups, building without"
-       @echo "specifying the target is no longer supported. Please specify the"
-       @echo "target OS in the TARGET variable, in the following form:"
+       @echo "Usage:"
        @echo
-       @echo "   $ make TARGET=xxx"
+       @echo "    $ make help                       # To print a full explanation."
+       @echo "    $ make TARGET=xxx USE_<feature>=1 # To build HAProxy."
        @echo
-       @echo "Please choose the target among the following supported list :"
+       @echo "The most commonly used targets are:"
        @echo
-       @echo "   linux-glibc, linux-glibc-legacy, linux-musl, solaris, freebsd, dragonfly, "
-       @echo "   openbsd, netbsd, cygwin, haiku, aix51, aix52, aix72-gcc, osx, generic, "
-       @echo "   custom"
+       @echo "    linux-glibc    - Modern Linux with glibc"
+       @echo "    linux-musl     - Modern Linux with musl"
+       @echo "    freebsd        - FreeBSD"
+       @echo "    openbsd        - OpenBSD"
+       @echo "    netbsd         - NetBSD"
+       @echo "    osx            - macOS"
+       @echo "    solaris        - Solaris"
        @echo
-       @echo "Use \"generic\" if you don't want any optimization, \"custom\" if you"
-       @echo "want to precisely tweak every option, or choose the target which"
-       @echo "matches your OS the most in order to gain the maximum performance"
-       @echo "out of it. Please check the Makefile in case of doubts."
+       @echo "Choose the target which matches your OS the most in order to"
+       @echo "gain the maximum performance out of it."
+       @echo
+       @echo "Common features you might want to include in your build are:"
+       @echo
+       @echo "    USE_OPENSSL=1 - Support for TLS encrypted connections"
+       @echo "    USE_ZLIB=1    - Support for HTTP response compression"
+       @echo "    USE_PCRE=1    - Support for PCRE regular expressions"
+       @echo "    USE_LUA=1     - Support for dynamic processing using Lua"
+       @echo
+       @echo "Use 'make help' to print a full explanation of supported targets"
+       @echo "and features."
        @echo
        @exit 1
 else