Sync configure.ac with configure script

Fallback from bade6276d16523f81a1dedf22e591730592f15d6

diff --git a/configure.ac b/configure.ac
index b1a1530dba8940cd63b72d517562b170e84af4b1..69bbbded5a74a97bcfbf4a9e0125e3a3c0a07e00 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1089,16 +1089,10 @@ if test -n "$CXX"; then
   # In theory the clang and gcc regexes can be merged, but the
   # result is incomprehensible.
   if test "$with_clang" != no; then
-  find_cxx_header () {
-    echo "#include <$1>" | $CXX -M -MP -x c++ - 2>/dev/null \
-        | sed -n "\,^[o.-]*[ :] /.*/$1 [\]$,{s,^[o.-]*[ :] /,/,;s/ [\]$//;p}"
-  }
-  else
   find_cxx_header () {
     echo "#include <$1>" | $CXX -M -MP -x c++ - 2>/dev/null \
         | sed -n "\,$1:,{s/:\$//;p}"
   }
-  fi
   CXX_CSTDLIB_HEADER="$(find_cxx_header cstdlib)"
   CXX_CMATH_HEADER="$(find_cxx_header cmath)"
   CXX_BITS_STD_ABS_H="$(find_cxx_header bits/std_abs.h)"