diff --git a/src/add-ons/kernel/bus_managers/pci/arch/x86/pci_config.c b/src/add-ons/kernel/bus_managers/pci/arch/x86/pci_config.c
index 36d4665094..d872854bbb 100644
--- a/src/add-ons/kernel/bus_managers/pci/arch/x86/pci_config.c
+++ b/src/add-ons/kernel/bus_managers/pci/arch/x86/pci_config.c
@@ -244,5 +244,5 @@ pci_mech2_write_config(uint8 bus, uint8 device, uint8 function, uint8 offset, ui
 void *
 pci_ram_address(const void *physical_address_in_system_memory)
 {
-	return physical_address_in_system_memory;
+	return (void *)physical_address_in_system_memory;
 }
diff --git a/src/add-ons/kernel/drivers/arch/x86/floppy/floppy.c b/src/add-ons/kernel/drivers/arch/x86/floppy/floppy.c
index 2f9d2f9c5d..528f0177bc 100644
--- a/src/add-ons/kernel/drivers/arch/x86/floppy/floppy.c
+++ b/src/add-ons/kernel/drivers/arch/x86/floppy/floppy.c
@@ -98,7 +98,7 @@ typedef struct floppy_cookie {
 } floppy_cookie;
 
 
-static int motor_off_daemon(void *t, int tim);
+static void motor_off_daemon(void *t, int tim);
 
 
 status_t
@@ -521,7 +521,7 @@ flo_control(floppy_cookie *cookie, uint32 op, void *data, size_t len)
 }
 
 
-static int
+static void
 motor_off_daemon(void *t, int tim)
 {
 	int i;
@@ -535,7 +535,6 @@ motor_off_daemon(void *t, int tim)
 			}
 		}
 	}
-	return 0;
 }
 
 
diff --git a/src/add-ons/kernel/drivers/audio/ac97/auvia/ac97.c b/src/add-ons/kernel/drivers/audio/ac97/auvia/ac97.c
index e8b20c4c81..36f99668a7 100644
--- a/src/add-ons/kernel/drivers/audio/ac97/auvia/ac97.c
+++ b/src/add-ons/kernel/drivers/audio/ac97/auvia/ac97.c
@@ -176,7 +176,7 @@ codec_table codecs[] =
 	{ 0x00000000, 0x00000000, &default_ops, "Unknown" } /* must be last one, matches every codec */
 };
 
-codec_table *
+static codec_table *
 find_codec_table(uint32 codecid)
 {
 	codec_table *codec;
diff --git a/src/add-ons/kernel/drivers/audio/ac97/ich/ich.c b/src/add-ons/kernel/drivers/audio/ac97/ich/ich.c
index 17dfd1ff82..07f4242468 100644
--- a/src/add-ons/kernel/drivers/audio/ac97/ich/ich.c
+++ b/src/add-ons/kernel/drivers/audio/ac97/ich/ich.c
@@ -324,7 +324,7 @@ init_hardware(void)
 }
 
 
-void 
+static void 
 dump_hardware_regs()
 {
 	LOG(("GLOB_CNT = %#08x\n",ich_reg_read_32(ICH_REG_GLOB_CNT)));
@@ -345,19 +345,19 @@ dump_hardware_regs()
 	LOG(("PO ICH_REG_X_CR = %#x\n",ich_reg_read_8(ICH_REG_X_CR + ICH_REG_PO_BASE)));
 }
 
-uint16
+static uint16
 ac97_reg_read(void *cookie, uint8 reg)
 {
 	return ich_codec_read(config->codecoffset + reg);
 }
 
-void
+static void
 ac97_reg_write(void *cookie, uint8 reg, uint16 value)
 {
 	ich_codec_write(config->codecoffset + reg, value);
 }
 
-uint32
+static uint32
 ich_clock_get()
 {
 	uint32 civ1, civ2, picb;
@@ -402,7 +402,7 @@ ich_clock_get()
 	return rate;
 }
 
-void
+static void
 ich_clock_calibrate()
 {
 	uint32 rate;
diff --git a/src/add-ons/media/plugins/avi_reader/libOpenDML/OpenDMLFile.cpp b/src/add-ons/media/plugins/avi_reader/libOpenDML/OpenDMLFile.cpp
index 3f092cbe22..bb48f8146f 100644
--- a/src/add-ons/media/plugins/avi_reader/libOpenDML/OpenDMLFile.cpp
+++ b/src/add-ons/media/plugins/avi_reader/libOpenDML/OpenDMLFile.cpp
@@ -179,8 +179,10 @@ OpenDMLFile::InitData()
 				fStreamData[stream].odml_superindex_entry_pos = 0;
 			}
 			for (int i = 0; i < fStreamData[stream].odml_superindex_entry_count; i++) {
+#ifdef TRACE_ODML_FILE
 				odml_superindex_entry *entry = (odml_superindex_entry *) (fStreamData[stream].odml_superindex + i * fStreamData[stream].odml_superindex_entry_size);
 				TRACE("odml_superindex entry %d: start %10Ld, size %8ld, duration %lu\n", i, entry->start, entry->size, entry->duration);
+#endif
 			}
 		} else {
 			// this stream has no superindex, as it doesn't have an opendml index :=)
diff --git a/src/kernel/libroot/posix/glibc/libio/fcloseall.c b/src/kernel/libroot/posix/glibc/libio/fcloseall.c
index ae1f0b4a1f..f611e74428 100644
--- a/src/kernel/libroot/posix/glibc/libio/fcloseall.c
+++ b/src/kernel/libroot/posix/glibc/libio/fcloseall.c
@@ -28,8 +28,10 @@
 #include "libioP.h"
 #include <stdio.h>
 
+int __fcloseall(void);
+
 int
-__fcloseall ()
+__fcloseall (void)
 {
   /* Close all streams.  */
   return _IO_cleanup ();
diff --git a/src/kernel/libroot/posix/glibc/libio/getc_u.c b/src/kernel/libroot/posix/glibc/libio/getc_u.c
index 5c08dbc156..f0c19b4fa5 100644
--- a/src/kernel/libroot/posix/glibc/libio/getc_u.c
+++ b/src/kernel/libroot/posix/glibc/libio/getc_u.c
@@ -30,6 +30,8 @@
 
 #undef getc_unlocked
 
+int __getc_unlocked(FILE *fp);
+
 int
 __getc_unlocked (FILE *fp)
 {
diff --git a/src/kernel/libroot/posix/glibc/stdio-common/getline.c b/src/kernel/libroot/posix/glibc/stdio-common/getline.c
index 7b9ff5993a..35ac49242f 100644
--- a/src/kernel/libroot/posix/glibc/stdio-common/getline.c
+++ b/src/kernel/libroot/posix/glibc/stdio-common/getline.c
@@ -19,6 +19,7 @@
 #include <stddef.h>
 #include <stdio.h>
 
+ssize_t __getline(char **lineptr, size_t *n, FILE *stream);
 
 /** Like getdelim, but always looks for a newline. */
 
diff --git a/src/kernel/libroot/posix/glibc/stdio-common/printf-parse.h b/src/kernel/libroot/posix/glibc/stdio-common/printf-parse.h
index f605fbbaa8..8fbf8ff178 100644
--- a/src/kernel/libroot/posix/glibc/stdio-common/printf-parse.h
+++ b/src/kernel/libroot/posix/glibc/stdio-common/printf-parse.h
@@ -101,7 +101,7 @@ find_spec (const UCHAR_T *format)
 #else
   while (*format != L_('\0') && *format != L_('%'))
     {
-      int len;
+//      int len;
 
       /* Remove any hints of a wrong encoding.  */
 //      ps->__count = 0;
diff --git a/src/kernel/libroot/posix/glibc/stdio-common/snprintf.c b/src/kernel/libroot/posix/glibc/stdio-common/snprintf.c
index a880c4a126..ff3a1a9301 100644
--- a/src/kernel/libroot/posix/glibc/stdio-common/snprintf.c
+++ b/src/kernel/libroot/posix/glibc/stdio-common/snprintf.c
@@ -24,6 +24,8 @@
 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
 #endif
 
+int __snprintf(char *s, size_t maxlen, const char *format, ...);
+
 /* Write formatted output into S, according to the format
    string FORMAT, writing no more than MAXLEN characters.  */
 /* VARARGS3 */
diff --git a/src/kernel/libroot/posix/glibc/stdio-common/tempname.c b/src/kernel/libroot/posix/glibc/stdio-common/tempname.c
index 7227cfccd5..e46376052f 100644
--- a/src/kernel/libroot/posix/glibc/stdio-common/tempname.c
+++ b/src/kernel/libroot/posix/glibc/stdio-common/tempname.c
@@ -135,6 +135,10 @@
 # define uint64_t uintmax_t
 #endif
 
+int __path_search(char *tmpl, size_t tmpl_len, const char *dir,
+				  const char *pfx, int try_tmpdir);
+int __gen_tempname(char *tmpl, int kind);
+
 /* Return nonzero if DIR is an existent directory.  */
 static int
 direxists(const char *dir)