--- a/src/transcalc.c
+++ b/src/transcalc.c
@@ -37,6 +37,15 @@
 extern gint trc_file_load (FILE *, short);
 
 char version[] = "transcalc " VERSION;
+GtkWidget *main_body_window;
+GtkWidget *transtype_combo;
+
+short current_transtype;
+trans_win *twin;
+short statusint;
+trans_gui *tgui;
+gboolean statusexists;
+int main_window_width, main_window_height;
 
 
 /*
--- a/src/transcalc.h
+++ b/src/transcalc.h
@@ -53,8 +53,8 @@
 #endif /* HAVE_STRCPY */
 
 
-GtkWidget *main_body_window;
-GtkWidget *transtype_combo;
+extern GtkWidget *main_body_window;
+extern GtkWidget *transtype_combo;
 /*GtkWidget *status;*/
 
 #define MICROSTRIP 0
@@ -163,12 +163,12 @@
   gfloat electrical_params_value[NUMELECPARS];
 } trans_value;
 
-short current_transtype;
-trans_win *twin;
-short statusint;
-trans_gui *tgui;
-gboolean statusexists;
-int main_window_width, main_window_height;
+extern short current_transtype;
+extern trans_win *twin;
+extern short statusint;
+extern trans_gui *tgui;
+extern gboolean statusexists;
+extern int main_window_width, main_window_height;
 
 void error_mes(gchar * text);
 
--- a/src/unitscombo.c
+++ b/src/unitscombo.c
@@ -33,6 +33,7 @@
 #include "transcalc.h"
 #include "body.h"
 
+short length_unit, freq_unit, res_unit, ang_unit;
 
 gchar *length_unit_name[] = { "mil",
 			      "cm",
--- a/src/units.h
+++ b/src/units.h
@@ -77,6 +77,6 @@
 #define ohm_to_kohm(a) (a/1000.0)
 */
 
-short length_unit, freq_unit, res_unit, ang_unit;
+extern short length_unit, freq_unit, res_unit, ang_unit;
 
 #endif