Reveal struct winsize on Solaris.

On Solaris 10, we need __EXTENSIONS__ defined to make
struct winsize appear out of <termios.h>.

This commit adds detection for what preprocessor symbol needs
to be defined for struct winsize to appear, if it appears at
all. Then this symbol is defined on the compiler command line
when compiling linenoise.

* Makefile (CFLAGS): Add -D$(termios_define) for
linenoise.o target.

* configure (have_winsize, termios_define): New variables.
Detect whether struct winsize is available, and what
preprocessor symbol, if any, is required to reveal the
feature.

* linenoise/linenoise.c: Need to include TXR's "config.h"
for HAVE_WINSIZE.
(get_columns): Reorganized so that use of struct winsize
is guarded by HAVE_WINSIZE and fallback code is used if
either obtaining the size fails or the feature is completely
unavailable.

3 files changed, 39 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index c05ecb75..bc0b488e 100644
--- a/Makefile
+++ b/Makefile
@@ -233,6 +233,7 @@ dbg/txr-win.o: CFLAGS += -DPROG_NAME=\"$(PROG)-win-dbg\" \
 $(call EACH_CONF,txr.o txr-win.o): CFLAGS += -DEXE_SUFF=\"$(EXE)\"
 $(call EACH_CONF,txr.o txr-win.o): CFLAGS += -DTXR_VER=\"$(txr_ver)\"
 
+$(call EACH_CONF,linenoise/linenoise.o): CFLAGS += -D$(termios_define)
 .PHONY: rebuild clean repatch distclean
 
 ifeq ($(PROG),)
diff --git a/configure b/configure
index 36992329..fa72e0e0 100755
--- a/configure
+++ b/configure
@@ -124,6 +124,8 @@ have_git=
 have_pwuid=
 have_alloca=
 have_termios=
+have_winsize=
+termios_define=
 conf_dir=config
 config_h=$conf_dir/config.h
 config_make=$conf_dir/config.make
@@ -651,6 +653,7 @@ have_glob := $have_glob
 have_posix_sigs := $have_posix_sigs
 
 have_termios := $have_termios
+termios_define := $termios_define
 
 # do we compile in debug support?
 debug_support := $debug_support
@@ -2153,6 +2156,32 @@ else
   printf "no\n"
 fi
 
+printf "Checking for struct winsize ... "
+
+for termios_define in NOTHING __EXTENSIONS__ ; do
+  cat > conftest.c <<!
+#define $termios_define
+#include <sys/ioctl.h>
+#include <termios.h>
+
+int main(int argc, char **argv)
+{
+  struct winsize ws;
+  return 0;
+}
+!
+  if conftest ; then
+    printf "yes\n"
+    printf "#define HAVE_WINSIZE 1\n" >> $config_h
+    have_winsize=y
+    break;
+  fi
+done
+
+if [ -z "$have_winsize" ] ; then
+  printf "no\n"
+fi
+
 #
 # Dependent variables
 #
diff --git a/linenoise/linenoise.c b/linenoise/linenoise.c
index 63abef6c..791d99ed 100644
--- a/linenoise/linenoise.c
+++ b/linenoise/linenoise.c
@@ -53,6 +53,7 @@
 #include <sys/ioctl.h>
 #include <unistd.h>
 #include <signal.h>
+#include "config.h"
 #include "linenoise.h"
 
 #define LINENOISE_DEFAULT_HISTORY_MAX_LEN 100
@@ -211,10 +212,16 @@ static int get_cursor_position(int ifd, int ofd) {
 /* Try to get the number of columns in the current terminal, or assume 80
  * if it fails. */
 static int get_columns(int ifd, int ofd) {
+#if HAVE_WINSIZE
     struct winsize ws;
 
-    if (ioctl(1, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
-        /* ioctl() failed. Try to query the terminal itself. */
+    if (ioctl(1, TIOCGWINSZ, &ws) == 0 && ws.ws_col != 0)
+        return ws.ws_col;
+#endif
+
+    {
+        /* ioctl() failed or we don't have struct winsize.
+           Try to query the terminal itself. */
         int start, cols;
 
         /* Get the initial position so we can restore it later. */
@@ -235,8 +242,6 @@ static int get_columns(int ifd, int ofd) {
             }
         }
         return cols;
-    } else {
-        return ws.ws_col;
     }
 
 failed: