diff --git a/cmdgen.c b/cmdgen.c
index 265e5adc..d6c1f721 100644
--- a/cmdgen.c
+++ b/cmdgen.c
@@ -129,7 +129,9 @@ void sk_cleanup(void)
 
 void showversion(void)
 {
-    printf("puttygen: %s\n", ver);
+    char *buildinfo_text = buildinfo("\n");
+    printf("puttygen: %s\n%s", ver, buildinfo_text);
+    sfree(buildinfo_text);
 }
 
 void usage(int standalone)
diff --git a/misc.c b/misc.c
index 7a7cc194..06baf8d6 100644
--- a/misc.c
+++ b/misc.c
@@ -1147,3 +1147,65 @@ int strendswith(const char *s, const char *t)
     size_t slen = strlen(s), tlen = strlen(t);
     return slen >= tlen && !strcmp(s + (slen - tlen), t);
 }
+
+char *buildinfo(const char *newline)
+{
+    strbuf *buf = strbuf_new();
+
+    strbuf_catf(buf, "Build platform: %d-bit %s",
+                (int)(CHAR_BIT * sizeof(void *)),
+                BUILDINFO_PLATFORM);
+
+#ifdef __clang_version__
+    strbuf_catf(buf, "%sCompiler: clang %s", newline, __clang_version__);
+#elif defined __GNUC__ && defined __VERSION__
+    strbuf_catf(buf, "%sCompiler: gcc %s", newline, __VERSION__);
+#elif defined _MSC_VER
+    strbuf_catf(buf, "%sCompiler: Visual Studio", newline);
+#if _MSC_VER == 1900
+    strbuf_catf(buf, " 2015 / MSVC++ 14.0");
+#elif _MSC_VER == 1800
+    strbuf_catf(buf, " 2013 / MSVC++ 12.0");
+#elif _MSC_VER == 1700
+    strbuf_catf(buf, " 2012 / MSVC++ 11.0");
+#elif _MSC_VER == 1600
+    strbuf_catf(buf, " 2010 / MSVC++ 10.0");
+#elif  _MSC_VER == 1500
+    strbuf_catf(buf, " 2008 / MSVC++ 9.0");
+#elif  _MSC_VER == 1400
+    strbuf_catf(buf, " 2005 / MSVC++ 8.0");
+#elif  _MSC_VER == 1310
+    strbuf_catf(buf, " 2003 / MSVC++ 7.1");
+#else
+    strbuf_catf(buf, ", unrecognised version");
+#endif
+    strbuf_catf(buf, " (_MSC_VER=%d)", (int)_MSC_VER);
+#endif
+
+#ifdef NO_SECURITY
+    strbuf_catf(buf, "%sBuild option: NO_SECURITY", newline);
+#endif
+#ifdef NO_SECUREZEROMEMORY
+    strbuf_catf(buf, "%sBuild option: NO_SECUREZEROMEMORY", newline);
+#endif
+#ifdef NO_IPV6
+    strbuf_catf(buf, "%sBuild option: NO_IPV6", newline);
+#endif
+#ifdef NO_GSSAPI
+    strbuf_catf(buf, "%sBuild option: NO_GSSAPI", newline);
+#endif
+#ifdef STATIC_GSSAPI
+    strbuf_catf(buf, "%sBuild option: STATIC_GSSAPI", newline);
+#endif
+#ifdef UNPROTECT
+    strbuf_catf(buf, "%sBuild option: UNPROTECT", newline);
+#endif
+#ifdef FUZZING
+    strbuf_catf(buf, "%sBuild option: FUZZING", newline);
+#endif
+#ifdef DEBUG
+    strbuf_catf(buf, "%sBuild option: DEBUG", newline);
+#endif
+
+    return strbuf_to_str(buf);
+}
diff --git a/misc.h b/misc.h
index 9ab21a0b..32e7bc32 100644
--- a/misc.h
+++ b/misc.h
@@ -118,6 +118,8 @@ int get_ssh_uint32(int *datalen, const void **data, unsigned *ret);
  * form, check if it equals an ordinary C zero-terminated string. */
 int match_ssh_id(int stringlen, const void *string, const char *id);
 
+char *buildinfo(const char *newline);
+
 /*
  * Debugging functions.
  *
diff --git a/pscp.c b/pscp.c
index 9ea423fd..25a2a737 100644
--- a/pscp.c
+++ b/pscp.c
@@ -2263,7 +2263,9 @@ static void usage(void)
 
 void version(void)
 {
-    printf("pscp: %s\n", ver);
+    char *buildinfo_text = buildinfo("\n");
+    printf("pscp: %s\n%s\n", ver, buildinfo_text);
+    sfree(buildinfo_text);
     cleanup_exit(1);
 }
 
diff --git a/psftp.c b/psftp.c
index d35b8fa3..513f202b 100644
--- a/psftp.c
+++ b/psftp.c
@@ -2665,7 +2665,9 @@ static void usage(void)
 
 static void version(void)
 {
-  printf("psftp: %s\n", ver);
+  char *buildinfo_text = buildinfo("\n");
+  printf("psftp: %s\n%s\n", ver, buildinfo_text);
+  sfree(buildinfo_text);
   cleanup_exit(1);
 }
 
diff --git a/unix/gtkdlg.c b/unix/gtkdlg.c
index 34773137..4eb4b010 100644
--- a/unix/gtkdlg.c
+++ b/unix/gtkdlg.c
@@ -3701,9 +3701,10 @@ void about_box(void *window)
     gtk_widget_show(w);
 
     {
+        char *buildinfo_text = buildinfo("\n");
         char *label_text = dupprintf
-            ("%s\n\n%s\n\n%s",
-             appname, ver,
+            ("%s\n\n%s\n\n%s\n\n%s",
+             appname, ver, buildinfo_text,
              "Copyright " SHORT_COPYRIGHT_DETAILS ". All rights reserved");
         w = gtk_label_new(label_text);
         gtk_label_set_justify(GTK_LABEL(w), GTK_JUSTIFY_CENTER);
diff --git a/unix/gtkmain.c b/unix/gtkmain.c
index a7b4a4e9..c681b93d 100644
--- a/unix/gtkmain.c
+++ b/unix/gtkmain.c
@@ -287,10 +287,13 @@ static void help(FILE *fp) {
 }
 
 static void version(FILE *fp) {
-    if(fprintf(fp, "%s: %s\n", appname, ver) < 0 || fflush(fp) < 0) {
+    char *buildinfo_text = buildinfo("\n");
+    if(fprintf(fp, "%s: %s\n%s\n", appname, ver, buildinfo_text) < 0 ||
+       fflush(fp) < 0) {
 	perror("output error");
 	exit(1);
     }
+    sfree(buildinfo_text);
 }
 
 static struct gui_data *the_inst;
diff --git a/unix/unix.h b/unix/unix.h
index 029d32ff..76ec7531 100644
--- a/unix/unix.h
+++ b/unix/unix.h
@@ -30,6 +30,17 @@
 #define META_MANUAL_MASK (GDK_MOD1_MASK)
 #define JUST_USE_GTK_CLIPBOARD_UTF8 /* low-level gdk_selection_* fails */
 #define DEFAULT_CLIPBOARD GDK_SELECTION_CLIPBOARD /* OS X has no PRIMARY */
+
+#define BUILDINFO_PLATFORM "OS X (GTK)"
+
+#elif defined NOT_X_WINDOWS
+
+#define BUILDINFO_PLATFORM "Unix (pure GTK)"
+
+#else
+
+#define BUILDINFO_PLATFORM "Unix (GTK + X11)"
+
 #endif
 
 struct Filename {
diff --git a/unix/uxpgnt.c b/unix/uxpgnt.c
index 4f3dde2d..14f1366c 100644
--- a/unix/uxpgnt.c
+++ b/unix/uxpgnt.c
@@ -141,7 +141,9 @@ static void usage(void)
 
 static void version(void)
 {
-    printf("pageant: %s\n", ver);
+    char *buildinfo_text = buildinfo("\n");
+    printf("pageant: %s\n%s\n", ver, buildinfo_text);
+    sfree(buildinfo_text);
     exit(1);
 }
 
diff --git a/unix/uxplink.c b/unix/uxplink.c
index 82693ba8..bf55ea73 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -594,7 +594,9 @@ static void usage(void)
 
 static void version(void)
 {
-    printf("plink: %s\n", ver);
+    char *buildinfo_text = buildinfo("\n");
+    printf("plink: %s\n%s\n", ver, buildinfo_text);
+    sfree(buildinfo_text);
     exit(1);
 }
 
diff --git a/windows/pageant.rc b/windows/pageant.rc
index 91432cc7..b1756a64 100644
--- a/windows/pageant.rc
+++ b/windows/pageant.rc
@@ -36,14 +36,14 @@ BEGIN
 END
 
 /* Accelerators used: cl */
-213 DIALOG DISCARDABLE 140, 40, 214, 74
+213 DIALOG DISCARDABLE 140, 40, 214, 90
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "About Pageant"
 FONT 8, "MS Shell Dlg"
 BEGIN
-    DEFPUSHBUTTON "&Close", IDOK, 160, 56, 48, 14
-    PUSHBUTTON "View &Licence", 101, 6, 56, 70, 14
-    EDITTEXT 1000, 10, 6, 194, 48, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
+    DEFPUSHBUTTON "&Close", IDOK, 160, 72, 48, 14
+    PUSHBUTTON "View &Licence", 101, 6, 72, 70, 14
+    EDITTEXT 1000, 10, 6, 194, 64, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
 END
 
 /* No accelerators used */
diff --git a/windows/puttygen.rc b/windows/puttygen.rc
index 5c61ee7d..cd4072ea 100644
--- a/windows/puttygen.rc
+++ b/windows/puttygen.rc
@@ -29,14 +29,14 @@ BEGIN
 END
 
 /* Accelerators used: cl */
-213 DIALOG DISCARDABLE 140, 40, 214, 74
+213 DIALOG DISCARDABLE 140, 40, 214, 90
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "About PuTTYgen"
 FONT 8, "MS Shell Dlg"
 BEGIN
-    DEFPUSHBUTTON "&Close", IDOK, 160, 56, 48, 14
-    PUSHBUTTON "View &Licence", 101, 6, 56, 70, 14
-    EDITTEXT 1000, 10, 6, 194, 48, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
+    DEFPUSHBUTTON "&Close", IDOK, 160, 72, 48, 14
+    PUSHBUTTON "View &Licence", 101, 6, 72, 70, 14
+    EDITTEXT 1000, 10, 6, 194, 64, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
 END
 
 /* No accelerators used */
diff --git a/windows/win_res.rc2 b/windows/win_res.rc2
index 28e66320..92d39cd5 100644
--- a/windows/win_res.rc2
+++ b/windows/win_res.rc2
@@ -16,15 +16,15 @@ IDI_MAINICON ICON "putty.ico"
 IDI_CFGICON ICON "puttycfg.ico"
 
 /* Accelerators used: clw */
-IDD_ABOUTBOX DIALOG DISCARDABLE 140, 40, 214, 74
+IDD_ABOUTBOX DIALOG DISCARDABLE 140, 40, 270, 106
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "About PuTTY"
 FONT 8, "MS Shell Dlg"
 BEGIN
-    DEFPUSHBUTTON "&Close", IDOK, 160, 56, 48, 14
-    PUSHBUTTON "View &Licence", IDA_LICENCE, 6, 56, 70, 14
-    PUSHBUTTON "Visit &Web Site", IDA_WEB, 84, 56, 70, 14
-    EDITTEXT IDA_TEXT, 10, 6, 194, 48, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
+    DEFPUSHBUTTON "&Close", IDOK, 216, 88, 48, 14
+    PUSHBUTTON "View &Licence", IDA_LICENCE, 6, 88, 70, 14
+    PUSHBUTTON "Visit &Web Site", IDA_WEB, 140, 88, 70, 14
+    EDITTEXT IDA_TEXT, 10, 6, 250, 80, ES_READONLY | ES_MULTILINE | ES_CENTER, WS_EX_STATICEDGE
 END
 
 /* Accelerators used: aco */
diff --git a/windows/windlg.c b/windows/windlg.c
index 17327866..e29f1291 100644
--- a/windows/windlg.c
+++ b/windows/windlg.c
@@ -200,10 +200,12 @@ static INT_PTR CALLBACK AboutProc(HWND hwnd, UINT msg,
 	SetWindowText(hwnd, str);
 	sfree(str);
         {
+            char *buildinfo_text = buildinfo("\r\n");
             char *text = dupprintf
-                ("%s\r\n\r\n%s\r\n\r\n%s",
-                 appname, ver,
+                ("%s\r\n\r\n%s\r\n\r\n%s\r\n\r\n%s",
+                 appname, ver, buildinfo_text,
                  "\251 " SHORT_COPYRIGHT_DETAILS ". All rights reserved.");
+            sfree(buildinfo_text);
             SetDlgItemText(hwnd, IDA_TEXT, text);
             sfree(text);
         }
diff --git a/windows/winpgen.c b/windows/winpgen.c
index 8468f805..4dd8272a 100644
--- a/windows/winpgen.c
+++ b/windows/winpgen.c
@@ -297,10 +297,12 @@ static INT_PTR CALLBACK AboutProc(HWND hwnd, UINT msg,
 	}
 
         {
+            char *buildinfo_text = buildinfo("\r\n");
             char *text = dupprintf
-                ("PuTTYgen\r\n\r\n%s\r\n\r\n%s",
-                 ver,
+                ("PuTTYgen\r\n\r\n%s\r\n\r\n%s\r\n\r\n%s",
+                 ver, buildinfo_text,
                  "\251 " SHORT_COPYRIGHT_DETAILS ". All rights reserved.");
+            sfree(buildinfo_text);
             SetDlgItemText(hwnd, 1000, text);
             sfree(text);
         }
diff --git a/windows/winpgnt.c b/windows/winpgnt.c
index 06c5fac1..604d092f 100644
--- a/windows/winpgnt.c
+++ b/windows/winpgnt.c
@@ -152,10 +152,12 @@ static INT_PTR CALLBACK AboutProc(HWND hwnd, UINT msg,
     switch (msg) {
       case WM_INITDIALOG:
         {
+            char *buildinfo_text = buildinfo("\r\n");
             char *text = dupprintf
-                ("Pageant\r\n\r\n%s\r\n\r\n%s",
-                 ver,
+                ("Pageant\r\n\r\n%s\r\n\r\n%s\r\n\r\n%s",
+                 ver, buildinfo_text,
                  "\251 " SHORT_COPYRIGHT_DETAILS ". All rights reserved.");
+            sfree(buildinfo_text);
             SetDlgItemText(hwnd, 1000, text);
             sfree(text);
         }
diff --git a/windows/winplink.c b/windows/winplink.c
index 3b20a0ab..d916104e 100644
--- a/windows/winplink.c
+++ b/windows/winplink.c
@@ -223,7 +223,9 @@ static void usage(void)
 
 static void version(void)
 {
-    printf("plink: %s\n", ver);
+    char *buildinfo_text = buildinfo("\n");
+    printf("plink: %s\n%s\n", ver, buildinfo_text);
+    sfree(buildinfo_text);
     exit(1);
 }
 
diff --git a/windows/winstuff.h b/windows/winstuff.h
index b9602243..9829f087 100644
--- a/windows/winstuff.h
+++ b/windows/winstuff.h
@@ -27,6 +27,8 @@
 
 #include "winhelp.h"
 
+#define BUILDINFO_PLATFORM "Windows"
+
 struct Filename {
     char *path;
 };