Easier install by detecting SBCL core-compression.

Various Linux distributions provide SBCL without core-compression
enabled. On the other hand, Mac OSX (at least via `homebrew`) SBCL with
core-compression enabled.  To make installation easier, teach the make
process to detect core-compression, and use it if possible.

INSTALL.md

@@ -60,9 +60,9 @@ Now that the dependences are installed, just type make.
 
     make
 
-If using Mac OS X, and depending on how you did install `SBCL` and which
-version you have (the brew default did change recently), you might need to
-ask the Makefile to refrain from trying to compress your binary image:
+If your `SBCL` supports core compression, the make process will use it
+to generate a smaller binary.  To force disabling core compression, you
+may use:
 
     make COMPRESS_CORE=no
 
@@ -101,4 +101,3 @@ The `build` step install build dependencies in a debian jessie container,
 then `git clone` and build `pgloader` in `/opt/src/pgloader` and finally
 copy the resulting binary image in `/usr/local/bin/pgloader` so that it's
 easily available.
-

Makefile

@@ -35,27 +35,26 @@ BUILDAPP_CCL  = $(BUILDDIR)/bin/buildapp.ccl$(EXE)
 BUILDAPP_SBCL = $(BUILDDIR)/bin/buildapp.sbcl$(EXE)
 
 ifeq ($(CL),sbcl)
-BUILDAPP   = $(BUILDAPP_SBCL)
-CL_OPTS    = --no-sysinit --no-userinit
+BUILDAPP      = $(BUILDAPP_SBCL)
+BUILDAPP_OPTS = --require sb-posix                      \
+                --require sb-bsd-sockets                \
+                --require sb-rotate-byte
+CL_OPTS    = --noinform --no-sysinit --no-userinit
 else
 BUILDAPP   = $(BUILDAPP_CCL)
 CL_OPTS    = --no-init
 endif
 
-COMPRESS_CORE ?= yes
-
 ifeq ($(CL),sbcl)
+COMPRESS_CORE ?= $(shell $(CL) --noinform \
+                               --quit     \
+                               --eval '(when (member :sb-core-compression cl:*features*) (write-string "yes"))')
+
+endif
+
+# note: on Windows_NT, we never core-compress; see above.
 ifeq ($(COMPRESS_CORE),yes)
 COMPRESS_CORE_OPT = --compress-core
-else
-COMPRESS_CORE_OPT = 
-endif
-endif
-
-ifeq ($(CL),sbcl)
-BUILDAPP_OPTS =          --require sb-posix                      \
-                         --require sb-bsd-sockets                \
-                         --require sb-rotate-byte
 endif
 
 DEBUILD_ROOT = /tmp/pgloader

README.md

@@ -103,13 +103,9 @@ binary image, though it's possible to build using
 
     $ make CL=ccl pgloader
 
-Note that the `Makefile` uses the `--compress-core` option when using SBCL,
-that should be enabled in your local copy of `SBCL`. If that's not the case,
-it's probably because you did compile and install `SBCL` yourself, so that
-you have a decently recent version to use. Then you need to compile it with
-the `--with-sb-core-compression` option.
-
-You can also remove the `--compress-core` option that way:
+If using `SBCL` and it supports core compression, the make process will
+use it to generate a smaller binary.  To force disabling core
+compression, you may use:
 
     $ make COMPRESS_CORE=no pgloader