diff --git a/findutils/find.c b/findutils/find.c
index bbc97ecd4..f2e3c6d07 100644
--- a/findutils/find.c
+++ b/findutils/find.c
@@ -299,7 +299,7 @@ static int find_type(char *type)
 }
 #endif
 
-action*** parse_params(char **argv)
+static action*** parse_params(char **argv)
 {
 	action*** appp;
 	int cur_group = 0;
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 08dab26f0..bce06843b 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -876,7 +876,7 @@ static int get_next_history(void)
 
 #if ENABLE_FEATURE_EDITING_SAVEHISTORY
 /* state->flags is already checked to be nonzero */
-void load_history(const char *fromfile)
+static void load_history(const char *fromfile)
 {
 	FILE *fp;
 	int hi;
@@ -910,7 +910,7 @@ void load_history(const char *fromfile)
 }
 
 /* state->flags is already checked to be nonzero */
-void save_history(const char *tofile)
+static void save_history(const char *tofile)
 {
 	FILE *fp;
 
diff --git a/libbb/makedev.c b/libbb/makedev.c
index 4903e4783..81cd82baf 100644
--- a/libbb/makedev.c
+++ b/libbb/makedev.c
@@ -13,6 +13,9 @@
 #ifdef __GLIBC__
 /* At least glibc has horrendously large inline for this, so wrap it */
 /* uclibc people please check - do we need "&& !__UCLIBC__" above? */
+
+/* suppress gcc "no previous prototype" warning */
+unsigned long long bb_makedev(unsigned int major, unsigned int minor);
 unsigned long long bb_makedev(unsigned int major, unsigned int minor)
 {
 	return makedev(major, minor);
diff --git a/libbb/perror_nomsg.c b/libbb/perror_nomsg.c
index 8059f9fd8..62ce888ae 100644
--- a/libbb/perror_nomsg.c
+++ b/libbb/perror_nomsg.c
@@ -13,6 +13,8 @@
 //#include "libbb.h"
 extern void bb_perror_msg(const char *s, ...);
 
+/* suppress gcc "no previous prototype" warning */
+void bb_perror_nomsg(void);
 void bb_perror_nomsg(void)
 {
 	bb_perror_msg(0);
diff --git a/libbb/perror_nomsg_and_die.c b/libbb/perror_nomsg_and_die.c
index c416df67c..dab3df60a 100644
--- a/libbb/perror_nomsg_and_die.c
+++ b/libbb/perror_nomsg_and_die.c
@@ -13,6 +13,8 @@
 //#include "libbb.h"
 extern void bb_perror_msg_and_die(const char *s, ...);
 
+/* suppress gcc "no previous prototype" warning */
+void bb_perror_nomsg_and_die(void);
 void bb_perror_nomsg_and_die(void)
 {
 	bb_perror_msg_and_die(0);
diff --git a/procps/ps.c b/procps/ps.c
index 12f6b65d1..acd9a3065 100644
--- a/procps/ps.c
+++ b/procps/ps.c
@@ -13,17 +13,17 @@
 
 /* Print value to buf, max size+1 chars (including trailing '\0') */
 
-void func_user(char *buf, int size, const procps_status_t *ps)
+static void func_user(char *buf, int size, const procps_status_t *ps)
 {
 	safe_strncpy(buf, get_cached_username(ps->uid), size+1);
 }
 
-void func_comm(char *buf, int size, const procps_status_t *ps)
+static void func_comm(char *buf, int size, const procps_status_t *ps)
 {
 	safe_strncpy(buf, ps->comm, size+1);
 }
 
-void func_args(char *buf, int size, const procps_status_t *ps)
+static void func_args(char *buf, int size, const procps_status_t *ps)
 {
 	buf[0] = '\0';
 	if (ps->cmd)
@@ -32,22 +32,22 @@ void func_args(char *buf, int size, const procps_status_t *ps)
 		snprintf(buf, size+1, "[%.*s]", size-2, ps->comm);
 }
 
-void func_pid(char *buf, int size, const procps_status_t *ps)
+static void func_pid(char *buf, int size, const procps_status_t *ps)
 {
 	snprintf(buf, size+1, "%*u", size, ps->pid);
 }
 
-void func_ppid(char *buf, int size, const procps_status_t *ps)
+static void func_ppid(char *buf, int size, const procps_status_t *ps)
 {
 	snprintf(buf, size+1, "%*u", size, ps->ppid);
 }
 
-void func_pgid(char *buf, int size, const procps_status_t *ps)
+static void func_pgid(char *buf, int size, const procps_status_t *ps)
 {
 	snprintf(buf, size+1, "%*u", size, ps->pgid);
 }
 
-void func_rss(char *buf, int size, const procps_status_t *ps)
+static void func_rss(char *buf, int size, const procps_status_t *ps)
 {
 	char buf5[5];
 	smart_ulltoa5( ((unsigned long long)ps->rss) << 10, buf5);