diff --git a/cmdgen.c b/cmdgen.c
index f1cf9770..9d9d011a 100644
--- a/cmdgen.c
+++ b/cmdgen.c
@@ -227,6 +227,9 @@ static char *readpassphrase(const char *filename)
 
 #define DEFAULT_RSADSA_BITS 2048
 
+/* For Unix in particular, but harmless if this main() is reused elsewhere */
+const int buildinfo_gtk_relevant = FALSE;
+
 int main(int argc, char **argv)
 {
     char *infile = NULL;
diff --git a/fuzzterm.c b/fuzzterm.c
index 21e7b12a..15b5d635 100644
--- a/fuzzterm.c
+++ b/fuzzterm.c
@@ -6,6 +6,9 @@
 #include "putty.h"
 #include "terminal.h"
 
+/* For Unix in particular, but harmless if this main() is reused elsewhere */
+const int buildinfo_gtk_relevant = FALSE;
+
 int main(int argc, char **argv)
 {
 	char blk[512];
diff --git a/testbn.c b/testbn.c
index 2ea4f459..05f62767 100644
--- a/testbn.c
+++ b/testbn.c
@@ -33,6 +33,9 @@ int random_byte(void)
 
 #define fromxdigit(c) ( (c)>'9' ? ((c)&0xDF) - 'A' + 10 : (c) - '0' )
 
+/* For Unix in particular, but harmless if this main() is reused elsewhere */
+const int buildinfo_gtk_relevant = FALSE;
+
 int main(int argc, char **argv)
 {
     char *buf;
diff --git a/unix/gtkapp.c b/unix/gtkapp.c
index 249be2d3..8b2a794f 100644
--- a/unix/gtkapp.c
+++ b/unix/gtkapp.c
@@ -127,6 +127,8 @@ https://wiki.gnome.org/Projects/GTK%2B/OSX/Bundling has some links.
 
 char *x_get_default(const char *key) { return NULL; }
 
+const int buildinfo_gtk_relevant = TRUE;
+
 #if !GTK_CHECK_VERSION(3,0,0)
 /* This front end only works in GTK 3. If that's not what we've got,
  * it's easier to just turn this program into a trivial stub by ifdef
diff --git a/unix/gtkask.c b/unix/gtkask.c
index c2b582e9..8493807b 100644
--- a/unix/gtkask.c
+++ b/unix/gtkask.c
@@ -473,6 +473,8 @@ static int setup_gtk(const char *display)
     return ret;
 }
 
+const int buildinfo_gtk_relevant = TRUE;
+
 char *gtk_askpass_main(const char *display, const char *wintitle,
                        const char *prompt, int *success)
 {
diff --git a/unix/gtkmain.c b/unix/gtkmain.c
index c681b93d..c80da702 100644
--- a/unix/gtkmain.c
+++ b/unix/gtkmain.c
@@ -542,6 +542,8 @@ GtkWidget *make_gtk_toplevel_window(void *frontend)
 
 extern int cfgbox(Conf *conf);
 
+const int buildinfo_gtk_relevant = TRUE;
+
 int main(int argc, char **argv)
 {
     Conf *conf;
diff --git a/unix/unix.h b/unix/unix.h
index ea848d37..7ab2ca24 100644
--- a/unix/unix.h
+++ b/unix/unix.h
@@ -31,21 +31,29 @@
 #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)"
+#define BUILDINFO_PLATFORM_GTK "OS X (GTK)"
 #define BUILDINFO_GTK
 
 #elif defined NOT_X_WINDOWS
 
-#define BUILDINFO_PLATFORM "Unix (pure GTK)"
+#define BUILDINFO_PLATFORM_GTK "Unix (pure GTK)"
 #define BUILDINFO_GTK
 
 #else
 
-#define BUILDINFO_PLATFORM "Unix (GTK + X11)"
+#define BUILDINFO_PLATFORM_GTK "Unix (GTK + X11)"
 #define BUILDINFO_GTK
 
 #endif
 
+/* BUILDINFO_PLATFORM varies its expansion between the GTK and
+ * pure-CLI utilities, so that Unix Plink, PSFTP etc don't announce
+ * themselves incongruously as having something to do with GTK. */
+#define BUILDINFO_PLATFORM_CLI "Unix"
+extern const int buildinfo_gtk_relevant;
+#define BUILDINFO_PLATFORM (buildinfo_gtk_relevant ? \
+                            BUILDINFO_PLATFORM_GTK : BUILDINFO_PLATFORM_CLI)
+
 char *buildinfo_gtk_version(void);
 
 struct Filename {
diff --git a/unix/uxplink.c b/unix/uxplink.c
index a2607fbb..2d4259b9 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -607,6 +607,8 @@ void frontend_net_error_pending(void) {}
 const int share_can_be_downstream = TRUE;
 const int share_can_be_upstream = TRUE;
 
+const int buildinfo_gtk_relevant = FALSE;
+
 int main(int argc, char **argv)
 {
     int sending;
diff --git a/unix/uxsftp.c b/unix/uxsftp.c
index 794cc9cb..56f7a136 100644
--- a/unix/uxsftp.c
+++ b/unix/uxsftp.c
@@ -622,6 +622,8 @@ void frontend_net_error_pending(void) {}
 
 void platform_psftp_pre_conn_setup(void) {}
 
+const int buildinfo_gtk_relevant = FALSE;
+
 /*
  * Main program: do platform-specific initialisation and then call
  * psftp_main().