diff --git a/CHANGES b/CHANGES
index c3cac8669..a3c1cf0b4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,8 @@ CHANGES IN FLTK 1.1.7
 	- Documentation fixes (STR #571, STR #648, STR #692, STR
 	  #730, STR #744, STR #745, STR #931, STR #942, STR #960,
 	  STR #969)
+	- FLTK now enables large file support when available (STR
+	  #1087)
 	- Fl_Clock_Output depended on a time value that was the
 	  same as an unsigned long, which is incorrect for WIN64
 	  and VC++ 2005 (STR #1079)
diff --git a/configh.in b/configh.in
index a2ce28c2d..bb5ae15b6 100644
--- a/configh.in
+++ b/configh.in
@@ -255,6 +255,30 @@
 
 #undef HAVE_ALSA_ASOUNDLIB_H
 
+/*
+ * Do we have the long long type?
+ */
+
+#undef HAVE_LONG_LONG
+
+#ifdef HAVE_LONG_LONG
+#  define FLTK_LLFMT	"%lld"
+#  define FLTK_LLCAST	(long long)
+#else
+#  define FLTK_LLFMT	"%ld"
+#  define FLTK_LLCAST	(long)
+#endif /* HAVE_LONG_LONG */
+
+/*
+ * Do we have the strtoll() function?
+ */
+
+#undef HAVE_STRTOLL
+
+#ifndef HAVE_STRTOLL
+#  define strtoll(nptr,endptr,base) strtol((nptr), (endptr), (base))
+#endif /* !HAVE_STRTOLL */
+
 /*
  * End of "$Id$".
  */
diff --git a/configure.in b/configure.in
index d323ad612..cacd44433 100644
--- a/configure.in
+++ b/configure.in
@@ -389,6 +389,40 @@ AC_CHECK_FUNCS(localeconv)
 dnl FLTK library uses math library functions...
 AC_SEARCH_LIBS(pow, m)
 
+dnl Check for largefile support...
+AC_SYS_LARGEFILE
+
+dnl Define largefile options as needed...
+LARGEFILE=""
+if test x$enable_largefile != xno; then
+	LARGEFILE="-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE"
+
+	if test $ac_cv_sys_large_files = 1; then
+		LARGEFILE="$LARGEFILE -D_LARGE_FILES"
+	fi
+
+	if test $ac_cv_sys_file_offset_bits = 64; then
+		LARGEFILE="$LARGEFILE -D_FILE_OFFSET_BITS=64"
+	fi
+fi
+AC_SUBST(LARGEFILE)
+
+dnl Check for "long long" support...
+AC_CACHE_CHECK(for long long int, ac_cv_c_long_long,
+	[if test "$GCC" = yes; then
+		ac_cv_c_long_long=yes
+	else
+		AC_TRY_COMPILE(,[long long int i;],
+			ac_cv_c_long_long=yes,
+			ac_cv_c_long_long=no)
+	fi])
+
+if test $ac_cv_c_long_long = yes; then
+	AC_DEFINE(HAVE_LONG_LONG)
+fi
+
+AC_CHECK_FUNC(strtoll, AC_DEFINE(HAVE_STRTOLL))
+
 dnl Check for audio libraries...
 AUDIOLIBS=""
 
diff --git a/makeinclude.in b/makeinclude.in
index 7985a50ff..e87c95eb5 100644
--- a/makeinclude.in
+++ b/makeinclude.in
@@ -55,8 +55,8 @@ MAKEDEPEND	= @MAKEDEPEND@
 
 # flags for C++ compiler:
 OPTIM		= @OPTIM@
-CFLAGS		= $(OPTIM) @CPPFLAGS@ @CFLAGS@
-CXXFLAGS	= $(OPTIM) @CPPFLAGS@ @CXXFLAGS@
+CFLAGS		= $(OPTIM) @LARGEFILE@ @CPPFLAGS@ @CFLAGS@
+CXXFLAGS	= $(OPTIM) @LARGEFILE@ @CPPFLAGS@ @CXXFLAGS@
 
 # program to make the archive:
 LIBNAME		= @LIBNAME@