Fix m4 quoting / clang 10 recognition

build/autotools/includes/depend.m4

@@ -7,8 +7,8 @@ dnl
 AC_DEFUN([EGG_CHECK_DEPMODE],
 [
 CCDEPMODE=gcc
-num=`$CXX -dumpversion | sed "s/^\\\(.\\\).*/\\\1/"`
-if test $num -ge "3"; then
+num=`$CXX -dumpversion | [ sed "s/^\([^.]*\).*/\1/" ]`
+if [[ "$num" -ge "3" ]]; then
   CCDEPMODE=gcc3
 #  GCC3="-Wpadded -Wpacked -Wno-unused-parameter -Wmissing-format-attribute -Wdisabled-optimization"
   GCC3_CFLAGS="-W -Wno-unused-parameter -Wdisabled-optimization -Wno-write-strings -Wno-format-security -Wno-format-y2k"

configure

@@ -4083,8 +4083,8 @@ fi
 
 
 CCDEPMODE=gcc
-num=`$CXX -dumpversion | sed "s/^\\\(.\\\).*/\\\1/"`
-if test $num -ge "3"; then
+num=`$CXX -dumpversion |  sed "s/^\([^.]*\).*/\1/" `
+if [ "$num" -ge "3" ]; then
   CCDEPMODE=gcc3
 #  GCC3="-Wpadded -Wpacked -Wno-unused-parameter -Wmissing-format-attribute -Wdisabled-optimization"
   GCC3_CFLAGS="-W -Wno-unused-parameter -Wdisabled-optimization -Wno-write-strings -Wno-format-security -Wno-format-y2k"