[mm-common] extra-install-cmd.py: Ignore FileNotFoundError

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 5224ea90bb1a8811763f43d1d51e906a84181b71
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Fri Apr 16 19:10:25 2021 +0200

    extra-install-cmd.py: Ignore FileNotFoundError
    
    util/meson_aux/extra-install-cmd.py: Ignore FileNotFoundError.
    On Windows, subprocess.run() may fail to find aclocal even if
    the calling meson.build file has found it. Ignore this case.
    
    https://mail.gnome.org/archives/gtkmm-list/2021-April/msg00005.html

 util/meson_aux/extra-install-cmd.py | 41 ++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 17 deletions(-)
---
diff --git a/util/meson_aux/extra-install-cmd.py b/util/meson_aux/extra-install-cmd.py
index 8414847..2b6d4e2 100755
--- a/util/meson_aux/extra-install-cmd.py
+++ b/util/meson_aux/extra-install-cmd.py
@@ -14,30 +14,37 @@ if not os.getenv('DESTDIR'):
   # not known to aclocal will not be picked up automatically.
   # (Starting with Python 3.7 text=True is a more understandable equivalent to
   # universal_newlines=True. Let's use only features in Python 3.5.)
-  result = subprocess.run(['aclocal', '--print-ac-dir'],
-                          stdout=subprocess.PIPE, stderr=subprocess.DEVNULL,
-                          universal_newlines=True)
-  acdir = result.stdout
-  aclocal_path = os.getenv('ACLOCAL_PATH')
-  # acdir and aclocal_path can be sequences of os.pathsep-separated paths.
-  # Merge them to one sequence with leading and trailing os.pathsep.
-  # os.pathsep is ':' for Linux, ';' for Windows.
-  acdirs = os.pathsep
-  if aclocal_path:
-    acdirs += aclocal_path + os.pathsep
-  if acdir:
-    acdirs += acdir + os.pathsep
+  try:
+    result = subprocess.run(['aclocal', '--print-ac-dir'],
+                            stdout=subprocess.PIPE, stderr=subprocess.DEVNULL,
+                            universal_newlines=True)
+    acdir = result.stdout
+    aclocal_path = os.getenv('ACLOCAL_PATH')
+    # acdir and aclocal_path can be sequences of os.pathsep-separated paths.
+    # Merge them to one sequence with leading and trailing os.pathsep.
+    # os.pathsep is ':' for Linux, ';' for Windows.
+    acdirs = os.pathsep
+    if aclocal_path:
+      acdirs += aclocal_path + os.pathsep
+    if acdir:
+      acdirs += acdir.rstrip('\n') + os.pathsep
 
-  if (os.pathsep + sys.argv[1] + os.pathsep) not in acdirs:
-    # f'''.....''' would require Python 3.6. Avoid it.
-    print('''\
+    if (os.pathsep + sys.argv[1] + os.pathsep) not in acdirs:
+      # f'''.....''' would require Python 3.6. Avoid it.
+      print('''\
                 NOTE
                 ----
+(If you don't intend to use Autotools, you can ignore this note.)
 The mm-common Autoconf macro files have been installed in a different
 directory than the system aclocal directory. In order for the installed
 macros to be found, it may be necessary to add the mm-common include
 path to the ACLOCAL_PATH environment variable:
   ACLOCAL_PATH="$ACLOCAL_PATH:{}"
   export ACLOCAL_PATH'''.format(sys.argv[1])
-    )
+      )
+  except FileNotFoundError:
+    # https://mail.gnome.org/archives/gtkmm-list/2021-April/msg00005.html
+    # On Windows, subprocess.run() may fail to find aclocal even if
+    # the calling meson.build file has found it. Ignore this case.
+    pass
 sys.exit(0)