Add a before-configure hook for kumo.

Objective: disable kumo build on hosts with broken gcc, as we don't want to
build our own gcc (yet ?).
This is not used yet, but should be within a few hours.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@41093 20353a03-c40f-0410-a6d1-a30d3c3de9de

buildout/hooks/kumo-hooks.py

+import os
+import sys
+import traceback
+from shutil import copy
+from subprocess import Popen, PIPE
+
+CONFIGURE_PATH = os.path.join('configure')
+CONFIGURE_BACKUP_PATH = CONFIGURE_PATH + '_disabled'
+# Fake configure, generating a fake Makefile which will create a marker file
+# instead of actually installing anything.
+# This is needed (?) to fetch --prefix from configure parameters, so we know
+# where to tell Makefile to put the dummy file.
+FAKE_CONFIGURE = '''#!%(python)s -S
+import os
+import sys
+print 'Configuration is disabled on this host because %%s'
+print 'Original configure file available at %(backup)s'
+prefix = None
+next = False
+for arg in sys.argv:
+    if next:
+        prefix = arg
+        break
+    if arg.startswith('--prefix'):
+        if arg.startswith('--prefix='):
+            _, prefix = arg.split('=', 1)
+            break
+        next = True
+if prefix is None:
+    raise '--prefix parameter not found'
+# Generate Makefile with proper prefix
+open('Makefile', 'w').write("""all:
+\techo 'make disabled, see configure'
+
+install:
+\ttouch %%%%s""" %%%% (
+  os.path.join(prefix, 'BUILD_DISABLED_BY_BUILDOUT'),
+))
+sys.exit(0)
+''' % {
+    'backup': CONFIGURE_BACKUP_PATH,
+    'python': sys.executable,
+}
+
+def pre_configure_hook(options, buildout):
+    gcc_executable = os.getenv('CC', 'gcc')
+    try:
+        gcc = Popen([gcc_executable, '-v'], stdout=PIPE, stderr=PIPE,
+            close_fds=True)
+    except OSError, (errno, _):
+        if errno == 2:
+            # No gcc installed, nothing to check
+            pass
+        else:
+            print 'Unexpected failure trying to detect gcc version'
+            traceback.print_exc()
+    else:
+        gcc.wait()
+        # Considered innocent until proven guilty.
+        error = None
+        for line in '\n'.join((gcc.stdout.read(), gcc.stderr.read())).splitlines():
+            if line.startswith('gcc version'):
+                if '4.1.1' in line and 'prerelease' in line:
+                    # There is a bug in 4.1.1 prerelease (ie, as of mandriva
+                    # 2007.0) g++ preventing kumo compilation from succeeding.
+                    error = 'broken GCC version: %s' % (line, )
+                break
+        else:
+            print >>sys.stderr, 'GCC version could not be detected, ' \
+                'building anyway'
+        if error is not None:
+            print 'Disabling build, with reason:', error
+            # Copy to preserver permission
+            copy(CONFIGURE_PATH, CONFIGURE_BACKUP_PATH)
+            open(CONFIGURE_PATH, 'w').write(FAKE_CONFIGURE % (error, ))
+