2 files changed, 12 insertions, 0 deletions

diff --git a/src/s/freebsd.h b/src/s/freebsd.h
index 59a1e9072e7..15bbe2b6426 100644
--- a/src/s/freebsd.h
+++ b/src/s/freebsd.h
@@ -167,3 +167,9 @@
    be seen again in a later read(2), without the CRs.  */
 
 #define BROKEN_PTY_READ_AFTER_EAGAIN 1
+
+/* Tell that garbage collector that setjmp is known to save all
+   registers relevant for conservative garbage collection in the
+   jmp_buf.  */
+
+#define GC_SETJMP_WORKS 1
diff --git a/src/s/msdos.h b/src/s/msdos.h
index 164f139949f..71794be5760 100644
--- a/src/s/msdos.h
+++ b/src/s/msdos.h
@@ -269,3 +269,9 @@ You lose; /* Emacs for DOS must be compiled with DJGPP */
 /* We need a little extra space, see ../../lisp/loadup.el */
 #define SYSTEM_PURESIZE_EXTRA 60000
 #endif
+
+/* Tell that garbage collector that setjmp is known to save all
+   registers relevant for conservative garbage collection in the
+   jmp_buf.  */
+
+#define GC_SETJMP_WORKS 1