Propagate source font modification time to svg during conversion.  Similar to
what upstream commit 95a470e941d9a20fbdaca51334e8b6b9d93cfae4 did for TTF
files.

Submitted upstream at http://github.com/fontforge/fontforge/pull/2696

--- a/fontforge/svg.c
+++ b/fontforge/svg.c
@@ -27,7 +27,6 @@
 #include "fontforgevw.h"
 #include <unistd.h>
 #include <math.h>
-#include <time.h>
 #include <locale.h>
 #include <utype.h>
 #include <chardata.h>
@@ -62,7 +61,6 @@ static int svg_outfontheader(FILE *file, SplineFont *sf,int layer) {
     BlueData bd;
     char *hash, *hasv, ch;
     int minu, maxu, i;
-    time_t now;
     const char *author = GetAuthor();
 
     memset(&info,0,sizeof(info));
@@ -78,9 +76,8 @@ static int svg_outfontheader(FILE *file, SplineFont *sf,int layer) {
 	fprintf( file, "\n-->\n" );
     }
     fprintf( file, "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" version=\"1.1\">\n" );
-    time(&now);
     fprintf( file, "<metadata>\nCreated by FontForge %d at %s",
-	    FONTFORGE_VERSIONDATE_RAW, ctime(&now) );
+	    FONTFORGE_VERSIONDATE_RAW, ctime((time_t*)&sf->modificationtime) );
     if ( author!=NULL )
 	fprintf(file," By %s\n", author);
     else
ef='/guix/tree/etc/completion/bash?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>tree</a><a href='/guix/commit/etc/completion/bash?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>commit</a><a href='/guix/diff/etc/completion/bash?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/completion/bash'>
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<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
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<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>root</a>/<a href='/guix/log/etc?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>etc</a>/<a href='/guix/log/etc/completion?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>completion</a>/<a href='/guix/log/etc/completion/bash?id=cad5c7543ad73b608bdb973aa99a2f78d9709796'>bash</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/completion/bash?id=cad5c7543ad73b608bdb973aa99a2f78d9709796&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-05-29 02:00:20 +0200'>2022-05-29</span></td><td><a href='/guix/commit/etc/completion/bash?id=dc6d92ac93cedd65f6c99daa530b69f43f6039ec'>bash completion: Fix &amp; unify option parsing.</a><span class='msg-avail'>...<span class='msg-tooltip'>We now correctly recognise ‘guix -Abcdef’ as equivalent to ‘guix -f’.

* etc/completion/bash/guix (_guix_is_short_option, guix_is_long_option):
New functions.
(_guix_is_dash_f, _guix_is_dash_l, _guix_is_dash_L, _guix_is_dash_m)
(_guix_is_dash_C, _guix_is_dash_p): Use them.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2022-01-17 19:05:48 +0100'>2022-01-17</span></td><td><a href='/guix/commit/etc/completion/bash?id=93d3a2b23cb264ae95e4478c28e3abd9ddcadd2d'>bash completion: Complete "guix home" sub-commands.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/completion/bash/guix (_guix_complete): Treat "guix home" like
"guix system".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-01-16 23:56:56 +0100'>2022-01-16</span></td><td><a href='/guix/commit/etc/completion/bash?id=e35deac9e7379605c0e3918e74a6d153861a4aa2'>bash completion: Fix options completion.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes, for example, "guix import pypi --&lt;TAB&gt;", which would previously
fail to show '--recursive'.

* etc/completion/bash/guix (_guix_complete_option): Fix options
completion for first subcommand.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Fulbert</td></tr>
<tr><td><span title='2021-12-08 21:09:55 +0100'>2021-12-08</span></td><td><a href='/guix/commit/etc/completion/bash?id=f3af1fb0bcbcbe18ab773374efe606e90107cfb6'>bash completion: Complete ‘guix shell -f’.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/completion/bash/guix (_guix_complete): Suggest a file name
following ‘guix shell […] -f’.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>