autotools, libtool, win32: add 'aarch64' support to the file magic test.

From libtool development commit 1638a6407573b74517b57a0f6e596918344a4394

acinclude/libtool.m4

@@ -2567,14 +2567,14 @@ cygwin* | mingw* | windows* | pw32* | cegcc*)
     cygwin*)
       # Cygwin DLLs use 'cyg' prefix rather than 'lib'
       #soname_spec='`echo $libname | sed -e 's/^lib/cyg/'``echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization.
 m4_if([$1], [],[
       sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"])
       ;;
     mingw* | windows* | cegcc*)
       # MinGW DLLs use traditional 'lib' prefix
       #soname_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization.
       ;;
     pw32*)
       # pw32 DLLs use 'pw' prefix rather than 'lib'
@@ -3486,7 +3486,7 @@ cygwin*)
   # func_win32_libid is a shell function defined in ltmain.sh
   lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
   lt_cv_file_magic_cmd='func_win32_libid'
-  lt_cv_deplibs_check_method=pass_all # SDL customization
+  lt_cv_deplibs_check_method=pass_all # SDL customization.
   ;;
 
 mingw* | windows* | pw32*)
@@ -3498,10 +3498,10 @@ mingw* | windows* | pw32*)
     lt_cv_file_magic_cmd='func_win32_libid'
   else
     # Keep this pattern in sync with the one in func_win32_libid.
-    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
+    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64|pe-aarch64)'
     lt_cv_file_magic_cmd='$OBJDUMP -f'
   fi
-  lt_cv_deplibs_check_method=pass_all # SDL customization
+  lt_cv_deplibs_check_method=pass_all # SDL customization.
   ;;
 
 cegcc*)

build-scripts/ltmain.sh

@@ -4935,7 +4935,7 @@ func_win32_libid ()
   *ar\ archive*) # could be an import, or static
     # Keep the egrep pattern in sync with the one in _LT_CHECK_MAGIC_METHOD.
     if eval $OBJDUMP -f $1 | $SED -e '10q' 2>/dev/null |
-       $EGREP 'file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)' >/dev/null; then
+       $EGREP 'file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64|pe-aarch64)' >/dev/null; then
       case $nm_interface in
       "MS dumpbin")
 	if func_cygming_ms_implib_p "$1" ||
@@ -6501,7 +6501,7 @@ func_mode_link ()
       # we shouldn't force the makefile maintainer to figure out
       # what system we are compiling for in order to pass an extra
       # flag for every libtool invocation.
-      # SDL customization: SDL code doesn't have any undefined symbols
+      # SDL customization: SDL code doesn't have any undefined symbols.
       allow_undefined=no
 
       # FIXME: Unfortunately, there are problems with the above when trying
@@ -6509,7 +6509,7 @@ func_mode_link ()
       # even a static library is built.  For now, we need to specify
       # -no-undefined on the libtool link line when we can be certain
       # that all symbols are satisfied, otherwise we get a static library.
-      # SDL customization: SDL code doesn't have any undefined symbols
+      # SDL customization: SDL code doesn't have any undefined symbols.
       # allow_undefined=yes
       ;;
     *)
@@ -8253,7 +8253,7 @@ func_mode_link ()
 	    elif test -n "$soname_spec"; then
 	      # bleh windows
 	      case $host_os in
-	      cygwin* | mingw* | windows* | cegcc*)  # | os2* # SDL customization: removed OS/2 versioning support.
+	      cygwin* | mingw* | windows* | cegcc*) # | os2* # SDL customization: removed OS/2 versioning support.
 	        func_arith $current - $age
 		major=$func_arith_result
 		versuffix=-$major

configure

@@ -5815,7 +5815,7 @@ cygwin*)
   # func_win32_libid is a shell function defined in ltmain.sh
   lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
   lt_cv_file_magic_cmd='func_win32_libid'
-  lt_cv_deplibs_check_method=pass_all # SDL customization
+  lt_cv_deplibs_check_method=pass_all # SDL customization.
   ;;
 
 mingw* | windows* | pw32*)
@@ -5827,10 +5827,10 @@ mingw* | windows* | pw32*)
     lt_cv_file_magic_cmd='func_win32_libid'
   else
     # Keep this pattern in sync with the one in func_win32_libid.
-    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
+    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64|pe-aarch64)'
     lt_cv_file_magic_cmd='$OBJDUMP -f'
   fi
-  lt_cv_deplibs_check_method=pass_all # SDL customization
+  lt_cv_deplibs_check_method=pass_all # SDL customization.
   ;;
 
 cegcc*)
@@ -11600,14 +11600,14 @@ cygwin* | mingw* | windows* | pw32* | cegcc*)
     cygwin*)
       # Cygwin DLLs use 'cyg' prefix rather than 'lib'
       #soname_spec='`echo $libname | sed -e 's/^lib/cyg/'``echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization.
 
       sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"
       ;;
     mingw* | windows* | cegcc*)
       # MinGW DLLs use traditional 'lib' prefix
       #soname_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization.
       ;;
     pw32*)
       # pw32 DLLs use 'pw' prefix rather than 'lib'
@@ -16984,13 +16984,13 @@ cygwin* | mingw* | windows* | pw32* | cegcc*)
     cygwin*)
       # Cygwin DLLs use 'cyg' prefix rather than 'lib'
       #soname_spec='`echo $libname | sed -e 's/^lib/cyg/'``echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | sed -e 's/^lib//'`$shared_ext' # SDL customization.
 
       ;;
     mingw* | windows* | cegcc*)
       # MinGW DLLs use traditional 'lib' prefix
       #soname_spec='$libname`echo $release | $SED -e 's/[[.]]/-/g'`$versuffix$shared_ext'
-      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization
+      soname_spec='`echo $libname | $SED -e 's/^lib//'`$shared_ext' # SDL customization.
       ;;
     pw32*)
       # pw32 DLLs use 'pw' prefix rather than 'lib'