compat: add canonicalize_file_name

the POSIX 2008 behaviour of realpath is not available everywhere so we
provide a simple wrapper function.  We use (and provide) the gnu
extension canonicalize_file_name to make it cleaner to test for the
feature we need; otherwise we have to rely on realpath segfaulting if
the second argument is null.

1 files changed, 16 insertions, 0 deletions

diff --git a/configure b/configure
index 1d430b9c..09f4650c 100755
--- a/configure
+++ b/configure
@@ -556,6 +556,18 @@ EOF
     exit 1
 fi
 
+printf "Checking for canonicalize_file_name... "
+if ${CC} -o compat/have_canonicalize_file_name "$srcdir"/compat/have_canonicalize_file_name.c > /dev/null 2>&1
+then
+    printf "Yes.\n"
+    have_canonicalize_file_name=1
+else
+    printf "No (will use our own instead).\n"
+    have_canonicalize_file_name=0
+fi
+rm -f compat/have_canonicalize_file_name
+
+
 printf "Checking for getline... "
 if ${CC} -o compat/have_getline "$srcdir"/compat/have_getline.c > /dev/null 2>&1
 then
@@ -802,6 +814,10 @@ zsh_completion_dir = ${ZSHCOMLETIONDIR:=\$(prefix)/share/zsh/functions/Completio
 
 # Whether the getline function is available (if not, then notmuch will
 # build its own version)
+HAVE_CANONICALIZE_FILE_NAME = ${have_canonicalize_file_name}
+
+# Whether the getline function is available (if not, then notmuch will
+# build its own version)
 HAVE_GETLINE = ${have_getline}
 
 # Whether the strcasestr function is available (if not, then notmuch will