Sylpheed-Claws-1.9.13 uses libetpan but on my system - 5.4-STABLE - it does not compile. Extras from the output:

/pango-1.0 -I/usr/local/include/freetype2 -I/usr/local/include -I/usr/local/include -I/usr/local/include -O -pipe -Wall -MT etpan-thread-manager.lo -MD -MP -MF .deps/etpan-thread-manager.Tpo -c etpan-thread-manager.c  -fPIC -DPIC -o .libs/etpan-thread-manager.o
In file included from etpan-thread-manager.h:5,
                 from etpan-thread-manager.c:7:
etpan-thread-manager-types.h:21: error: syntax error before "pthread_t"
etpan-thread-manager-types.h:45: error: syntax error before "pthread_mutex_t"
etpan-thread-manager.c: In function `etpan_thread_new':
etpan-thread-manager.c:83: error: structure has no member named `lock'
etpan-thread-manager.c:122: error: structure has no member named `lock'
etpan-thread-manager.c: In function `etpan_thread_free':
etpan-thread-manager.c:136: error: structure has no member named `lock'
etpan-thread-manager.c: In function `etpan_thread_op_new':
etpan-thread-manager.c:159: error: structure has no member named `lock'
etpan-thread-manager.c: In function `etpan_thread_op_free':
etpan-thread-manager.c:173: error: structure has no member named `lock'
etpan-thread-manager.c: In function `thread_lock':
etpan-thread-manager.c:251: error: structure has no member named `lock'
etpan-thread-manager.c: In function `thread_unlock':
etpan-thread-manager.c:256: error: structure has no member named `lock'
etpan-thread-manager.c: In function `etpan_thread_start':
etpan-thread-manager.c:325: error: structure has no member named `th_id'
etpan-thread-manager.c: In function `etpan_thread_join':
etpan-thread-manager.c:359: error: structure has no member named `th_id'
etpan-thread-manager.c: In function `etpan_thread_op_lock':
etpan-thread-manager.c:473: error: structure has no member named `lock'
etpan-thread-manager.c: In function `etpan_thread_op_unlock':
etpan-thread-manager.c:478: error: structure has no member named `lock'
gmake[4]: *** [etpan-thread-manager.lo] Error 1
gmake[4]: Leaving directory `/usr/ports/mail/sylpheed-claws/work/sylpheed-claws-1.9.13/src/etpan'
gmake[3]: *** [all-recursive] Error 1

Fix: create files/patch-src_etpan_etpan-thread-manager-types.h with the following content and rebuild.



#include <libetpan/libetpan.h>
+#include <pthread.h>

 struct etpan_thread_manager {
   /* thread pool */

Thanks to Alexander Leidinger and Ion-Mihai Tetcu--12G6iPqzDERgN6i9OLcULTm6Gl6cO5Ma9dTuYrb7vdGffE8g
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--- src/etpan/etpan-thread-manager-types.h.orig Tue Aug  2 15:17:58 2005
+++ src/etpan/etpan-thread-manager-types.h      Tue Aug  2 15:18:13 2005
@@ -3,6 +3,7 @@
 #define ETPAN_THREAD_MANAGER_TYPES_H
How-To-Repeat: Try to build Sylpheed-Claws-1.9.13 on 5.4-STABLE