Added support for leading dlsym underscore.

1 files changed, 38 insertions, 0 deletions

diff --git a/acinclude.m4 b/acinclude.m4
index c40eee99d..6a56d2696 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -102,3 +102,41 @@ ifelse([$4], , , [$4
 ])dnl
 fi
 ])
+
+
+
+dnl Check checks whether dlsym (if present) requires a leading underscore.
+dnl Written by Dan Hagerty <hag@ai.mit.edu> for scsh-0.5.0.
+AC_DEFUN(GUILE_DLSYM_USCORE, [
+  AC_MSG_CHECKING(for underscore before symbols)
+  AC_CACHE_VAL(guile_cv_uscore,[
+    echo "main(){int i=1;}
+    fnord(){int i=23; int ltuae=42;}" > conftest.c
+    ${CC} conftest.c > /dev/null
+    if (nm a.out | grep _fnord) > /dev/null; then
+      guile_cv_uscore=yes
+    else
+      guile_cv_uscore=no
+    fi])
+  AC_MSG_RESULT($guile_cv_uscore)
+  rm -f conftest.c a.out
+
+  if test $guile_cv_uscore = yes; then
+    AC_DEFINE(USCORE)
+
+    if test $ac_cv_func_dlopen = yes -o $ac_cv_lib_dl_dlopen = yes ; then
+	AC_MSG_CHECKING(whether dlsym always adds an underscore for us)
+	AC_CACHE_VAL(guile_cv_dlsym_adds_uscore,AC_TRY_RUN( [
+#include <dlfcn.h>
+#include <stdio.h>
+fnord() { int i=42;}
+main() { void *self, *ptr1, *ptr2; self=dlopen(NULL,RTLD_LAZY);
+    if(self) { ptr1=dlsym(self,"fnord"); ptr2=dlsym(self,"_fnord");
+    if(ptr1 && !ptr2) exit(0); } exit(1); } 
+], [guile_cv_dlsym_adds_uscore=yes
+	AC_DEFINE(DLSYM_ADDS_USCORE) ], guile_cv_dlsym_adds_uscore=no))
+
+        AC_MSG_RESULT($guile_cv_dlsym_adds_uscore)
+    fi
+  fi
+])