diff --git a/plugins/checksum/checksum.c b/plugins/checksum/checksum.c
index 6eb85e77..a4cadc19 100644
--- a/plugins/checksum/checksum.c
+++ b/plugins/checksum/checksum.c
@@ -170,22 +170,24 @@ dccrecv_cb (char *word[], void *userdata)
 	int result;
 	struct stat buffer;									/* buffer for storing file info */
 	char sum[65];											/* buffer for checksum */
-	char *file;
+	const char *file;
+	char *cfile;
+
 	if (hexchat_get_prefs (ph, "dcc_completed_dir", &file, NULL) == 1 && file[0] != 0)
 	{
-		file = g_strconcat (file, G_DIR_SEPARATOR_S, word[1], NULL);
+		cfile = g_strconcat (file, G_DIR_SEPARATOR_S, word[1], NULL);
 	}
 	else
 	{
-		file = g_strdup(word[2]);
+		cfile = g_strdup(word[2]);
 	}
 
-	result = stat (file, &buffer);
+	result = stat (cfile, &buffer);
 	if (result == 0)										/* stat returns 0 on success */
 	{
 		if (buffer.st_size <= (unsigned long long) get_limit () * 1048576)
 		{
-			sha256_file (file, sum);						/* file is the full filename even if completed dir set */
+			sha256_file (cfile, sum);						/* file is the full filename even if completed dir set */
 			/* try to print the checksum in the privmsg tab of the sender */
 			hexchat_set_context (ph, hexchat_find_context (ph, NULL, word[3]));
 			hexchat_printf (ph, "SHA-256 checksum for %s (local):  %s\n", word[1], sum);
@@ -201,7 +203,7 @@ dccrecv_cb (char *word[], void *userdata)
 		hexchat_printf (ph, "File access error!\n");
 	}
 
-	g_free (file);
+	g_free (cfile);
 	return HEXCHAT_EAT_NONE;
 }
 
diff --git a/plugins/python/python.c b/plugins/python/python.c
index 2e298c35..5f98c6c7 100644
--- a/plugins/python/python.c
+++ b/plugins/python/python.c
@@ -66,6 +66,7 @@
 #endif
 
 #include "hexchat-plugin.h"
+#undef _POSIX_C_SOURCE	/* Avoid warning: also in /usr/include/features.hfrom glib.h */
 #include "Python.h"
 #include "structmember.h"
 #include "pythread.h"
diff --git a/plugins/sysinfo/parse.c b/plugins/sysinfo/parse.c
index c1b478f8..76002900 100644
--- a/plugins/sysinfo/parse.c
+++ b/plugins/sysinfo/parse.c
@@ -37,9 +37,13 @@
 
 int xs_parse_cpu(char *model, char *vendor, double *freq, char *cache, unsigned int *count)
 {
-	char buffer[bsize], *pos;
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__) || defined(__alpha__) || defined(__ia64__) || defined(__parisc__) || defined(__sparc__)
+	char buffer[bsize];
+#endif
+#if defined(__powerpc__)
+	char *pos = NULL;
+#endif
 	FILE *fp = fopen("/proc/cpuinfo", "r");
-	pos = NULL;
 	if(fp == NULL)
 		return 1;
 	if(count != NULL) *count = 0;
diff --git a/src/common/outbound.c b/src/common/outbound.c
index 8241d78f..cc2d0e3e 100644
--- a/src/common/outbound.c
+++ b/src/common/outbound.c
@@ -1257,7 +1257,7 @@ cmd_menu (struct session *sess, char *tbuf, char *word[], char *word_eol[])
 	int idx = 2;
 	int len;
 	int pos = 0xffff;
-	int state;
+	int state = 0;
 	int toggle = FALSE;
 	int enable = TRUE;
 	int markup = FALSE;
diff --git a/src/common/plugin.c b/src/common/plugin.c
index d38085c5..c5b4aadc 100644
--- a/src/common/plugin.c
+++ b/src/common/plugin.c
@@ -1626,6 +1626,7 @@ hexchat_pluginpref_set_str_real (hexchat_plugin *pl, const char *var, const char
 	char *buffer;
 	char *buffer_tmp;
 	char line_buffer[512];		/* the same as in cfg_put_str */
+	char *line_bufp = line_buffer;
 	char *canon;
 
 	canon = g_strdup (pl->name);
@@ -1687,7 +1688,7 @@ hexchat_pluginpref_set_str_real (hexchat_plugin *pl, const char *var, const char
 	{
 		prevSetting = 0;
 
-		while (fscanf (fpIn, " %[^\n]", &line_buffer) != EOF)	/* read whole lines including whitespaces */
+		while (fscanf (fpIn, " %[^\n]", line_bufp) != EOF)	/* read whole lines including whitespaces */
 		{
 			buffer_tmp = g_strdup_printf ("%s ", var);	/* add one space, this way it works against var - var2 checks too */
 
@@ -1844,6 +1845,7 @@ hexchat_pluginpref_list (hexchat_plugin *pl, char* dest)
 	FILE *fpIn;
 	char confname[64];
 	char buffer[512];										/* the same as in cfg_put_str */
+	char *bufp = buffer;
 	char *token;
 
 	token = g_strdup (pl->name);
@@ -1860,7 +1862,7 @@ hexchat_pluginpref_list (hexchat_plugin *pl, char* dest)
 	else													/* existing config file, get list of settings */
 	{
 		strcpy (dest, "");									/* clean up garbage */
-		while (fscanf (fpIn, " %[^\n]", &buffer) != EOF)	/* read whole lines including whitespaces */
+		while (fscanf (fpIn, " %[^\n]", bufp) != EOF)	/* read whole lines including whitespaces */
 		{
 			token = strtok (buffer, "=");
 			strncat (dest, token, strlen (token) - 1);
diff --git a/src/common/text.c b/src/common/text.c
index a89fd511..0bef377c 100644
--- a/src/common/text.c
+++ b/src/common/text.c
@@ -136,7 +136,7 @@ scrollback_shrink (session *sess)
 	int fh;
 	int lines;
 	int line;
-	int len;
+	gsize len;
 	char *p;
 
 	scrollback_close (sess);
diff --git a/src/fe-gtk/fe-gtk.c b/src/fe-gtk/fe-gtk.c
index 2767fc52..a29a6fda 100644
--- a/src/fe-gtk/fe-gtk.c
+++ b/src/fe-gtk/fe-gtk.c
@@ -990,9 +990,9 @@ fe_set_inputbox_contents (session *sess, char *text)
 #ifndef WIN32
 
 static gboolean
-try_browser (const char *browser, const char *arg, const char *url)
+try_browser (const char *browser, char *arg, const char *url)
 {
-	const char *argv[4];
+	char *argv[4];
 	char *path;
 
 	path = g_find_program_in_path (browser);
@@ -1000,12 +1000,12 @@ try_browser (const char *browser, const char *arg, const char *url)
 		return 0;
 
 	argv[0] = path;
-	argv[1] = url;
+	argv[1] = (char *)url;
 	argv[2] = NULL;
 	if (arg)
 	{
 		argv[1] = arg;
-		argv[2] = url;
+		argv[2] = (char *)url;
 		argv[3] = NULL;
 	}
 	hexchat_execv (argv);
diff --git a/src/fe-gtk/gtkutil.c b/src/fe-gtk/gtkutil.c
index 0484de83..d032cf48 100644
--- a/src/fe-gtk/gtkutil.c
+++ b/src/fe-gtk/gtkutil.c
@@ -388,7 +388,7 @@ fe_get_str (char *msg, char *def, void *callback, void *userdata)
 										NULL);
 	gtk_box_set_homogeneous (GTK_BOX (GTK_DIALOG (dialog)->vbox), TRUE);
 
-	if ((int) userdata == 1)	/* nick box is usually on the very bottom, make it centered */
+	if (userdata == (void *)1)	/* nick box is usually on the very bottom, make it centered */
 	{
 		gtk_window_set_position (GTK_WINDOW (dialog), GTK_WIN_POS_CENTER);
 	}
diff --git a/src/fe-gtk/maingui.c b/src/fe-gtk/maingui.c
index a5ea0b66..2796b381 100644
--- a/src/fe-gtk/maingui.c
+++ b/src/fe-gtk/maingui.c
@@ -881,14 +881,11 @@ static int ul_tag = 0;
 static gboolean
 mg_populate_userlist (session *sess)
 {
-	session_gui *gui;
-
 	if (!sess)
 		sess = current_tab;
 
 	if (is_session (sess))
 	{
-		gui = sess->gui;
 		if (sess->type == SESS_DIALOG)
 			mg_set_access_icon (sess->gui, NULL, sess->server->is_away);
 		else
diff --git a/src/fe-gtk/sexy-spell-entry.c b/src/fe-gtk/sexy-spell-entry.c
index 48a6c383..aab82a7e 100644
--- a/src/fe-gtk/sexy-spell-entry.c
+++ b/src/fe-gtk/sexy-spell-entry.c
@@ -191,7 +191,6 @@ sexy_spell_entry_class_init(SexySpellEntryClass *klass)
 	GObjectClass *gobject_class;
 	GtkObjectClass *object_class;
 	GtkWidgetClass *widget_class;
-	GtkEntryClass *entry_class;
 
 	initialize_enchant();
 
@@ -200,7 +199,6 @@ sexy_spell_entry_class_init(SexySpellEntryClass *klass)
 	gobject_class = G_OBJECT_CLASS(klass);
 	object_class  = GTK_OBJECT_CLASS(klass);
 	widget_class  = GTK_WIDGET_CLASS(klass);
-	entry_class   = GTK_ENTRY_CLASS(klass);
 
 	if (have_enchant)
 		klass->word_check = default_word_check;
@@ -695,10 +693,6 @@ sexy_spell_entry_finalize(GObject *obj)
 static void
 sexy_spell_entry_destroy(GtkObject *obj)
 {
-	SexySpellEntry *entry;
-
-	entry = SEXY_SPELL_ENTRY(obj);
-
 	if (GTK_OBJECT_CLASS(parent_class)->destroy)
 		GTK_OBJECT_CLASS(parent_class)->destroy(obj);
 }
diff --git a/src/fe-gtk/xtext.c b/src/fe-gtk/xtext.c
index e2dc2b7c..6005e265 100644
--- a/src/fe-gtk/xtext.c
+++ b/src/fe-gtk/xtext.c
@@ -3729,13 +3729,13 @@ static void
 shade_image (GdkVisual *visual, void *data, int bpl, int bpp, int w, int h,
 				 int rm, int gm, int bm, int bg, int depth)
 {
+#ifdef USE_MMX
 	int bg_r, bg_g, bg_b;
 
 	bg_r = bg & visual->red_mask;
 	bg_g = bg & visual->green_mask;
 	bg_b = bg & visual->blue_mask;
 
-#ifdef USE_MMX
 	/* the MMX routines are about 50% faster at 16-bit. */
 	/* only use MMX routines with a pure black background */
 	if (bg_r == 0 && bg_g == 0 && bg_b == 0 && have_mmx ())	/* do a runtime check too! */