diff --git a/share/libc/malloc.h b/share/libc/malloc.h
index 3508e681088d7156a2c1ef1463ec483a387ca669..89992c10aea72c5a5bdde5caef588caf988166c4 100644
--- a/share/libc/malloc.h
+++ b/share/libc/malloc.h
@@ -21,4 +21,4 @@
 /**************************************************************************/
 
 // This file is not in the C standard; it exists for compatibility purposes
-#include <stdlib.h>
+#include "stdlib.h"
diff --git a/share/libc/memory.h b/share/libc/memory.h
index 4c1227c6134fc888153acd73db5fca43ba6b1bdd..767739595b490bb6f0e2ec0afee4168883959f7f 100644
--- a/share/libc/memory.h
+++ b/share/libc/memory.h
@@ -21,4 +21,4 @@
 /**************************************************************************/
 
 // This file is not in the C standard; it exists for compatibility purposes
-#include <string.h>
+#include "string.h"
diff --git a/share/libc/pthread.h b/share/libc/pthread.h
index d55ece32dee5c2f5a6c474d7495635726e9a7d5e..ac9f78bc234e099c4e77ec0690697b2173030e18 100644
--- a/share/libc/pthread.h
+++ b/share/libc/pthread.h
@@ -366,8 +366,8 @@ extern void pthread_testcancel(void);
 
 // From POSIX: "Inclusion of the <pthread.h> header shall make symbols defined
 //              in the headers <sched.h> and <time.h> visible."
-#include <sched.h>
-#include <time.h>
+//              (sched.h has already been included)
+#include "time.h"
 
 __POP_FC_STDLIB
 #endif
diff --git a/share/libc/pwd.h b/share/libc/pwd.h
index c93e3126becd9bd2cc455f9cd2783fa1d10ef277..7e12b710fbb93488ae04d18036a9c9d5079a586a 100644
--- a/share/libc/pwd.h
+++ b/share/libc/pwd.h
@@ -25,6 +25,7 @@
 #include "features.h"
 __PUSH_FC_STDLIB
 
+#include "__fc_builtin.h"
 #include "__fc_define_uid_and_gid.h"
 #include "__fc_string_axiomatic.h"
 
@@ -45,16 +46,12 @@ struct passwd {
 
 extern char __fc_getpwuid_pw_name[64];
 extern char __fc_getpwuid_pw_passwd[64];
-extern uid_t __fc_getpwuid_pw_uid;
-extern gid_t __fc_getpwuid_pw_gid;
 extern char __fc_getpwuid_pw_dir[64];
 extern char __fc_getpwuid_pw_shell[64];
 
 struct passwd __fc_pwd =
   {.pw_name = __fc_getpwuid_pw_name,
    .pw_passwd = __fc_getpwuid_pw_passwd,
-   .pw_uid = __fc_getpwuid_pw_uid,
-   .pw_gid = __fc_getpwuid_pw_gid,
    .pw_dir = __fc_getpwuid_pw_dir,
    .pw_shell = __fc_getpwuid_pw_shell};
 
diff --git a/share/libc/semaphore.h b/share/libc/semaphore.h
index 264a85bfeda14cc93d550b93bdae55e390fc78b6..765cd52cb54e180d73188d19c4973ee4b3eb615d 100644
--- a/share/libc/semaphore.h
+++ b/share/libc/semaphore.h
@@ -26,7 +26,7 @@
 #define __FC_SEMAPHORE
 #include "features.h"
 __PUSH_FC_STDLIB
-#include <time.h>
+#include "time.h"
 
 __BEGIN_DECLS
 
diff --git a/share/libc/time.h b/share/libc/time.h
index ffe74960d94212f40e32a517a2904e5ff256bbc4..60e5031571f9ef5e2d527e9b5e8a81907ae66a36 100644
--- a/share/libc/time.h
+++ b/share/libc/time.h
@@ -31,7 +31,7 @@ __PUSH_FC_STDLIB
 #include "__fc_string_axiomatic.h"
 
 #include "errno.h"
-
+#include "signal.h"
 /*
  * Names of the interval timers, and structure
  * defining a timer setting:
diff --git a/share/libc/unistd.h b/share/libc/unistd.h
index 3e790d2126994b6800877bfbed1493e67e19ebae..019c35bdad2fab505c9beb3be0f3c573f28a9e47 100644
--- a/share/libc/unistd.h
+++ b/share/libc/unistd.h
@@ -36,8 +36,8 @@ __PUSH_FC_STDLIB
 #include "__fc_define_intptr_t.h"
 #include "__fc_select.h"
 
-#include <getopt.h>
-#include <limits.h>
+#include "getopt.h"
+#include "limits.h"
 
 extern volatile int Frama_C_entropy_source;
 
diff --git a/share/libc/utmpx.h b/share/libc/utmpx.h
index cc1c85dc142c5fed93416b518f92ef9fc5e4d068..8e38de8057f31eb2173cd8c56e560dc8a8d0f98e 100644
--- a/share/libc/utmpx.h
+++ b/share/libc/utmpx.h
@@ -26,7 +26,7 @@
 __PUSH_FC_STDLIB
 
 #include "__fc_define_pid_t.h"
-#include <sys/time.h>
+#include "sys/time.h"
 
 __BEGIN_DECLS
 
diff --git a/src/plugins/variadic/tests/known/oracle/printf.res.oracle b/src/plugins/variadic/tests/known/oracle/printf.res.oracle
index 6468d9e5be5263ef8d9f565e6a6f053d9d7730bf..d3eac0b8fd4d4f2e18e10087b2a1bc0f9c5d0f3a 100644
--- a/src/plugins/variadic/tests/known/oracle/printf.res.oracle
+++ b/src/plugins/variadic/tests/known/oracle/printf.res.oracle
@@ -155,6 +155,7 @@
 /* Generated by Frama-C */
 #include "errno.h"
 #include "inttypes.h"
+#include "signal.h"
 #include "stdarg.h"
 #include "stddef.h"
 #include "stdint.h"
diff --git a/src/plugins/variadic/tests/known/oracle/swprintf.res.oracle b/src/plugins/variadic/tests/known/oracle/swprintf.res.oracle
index 304d4dc1977dc8951401f9d5e953da093460bcea..84ee5740088cec6cd2618b26d7d683bdb34bcea8 100644
--- a/src/plugins/variadic/tests/known/oracle/swprintf.res.oracle
+++ b/src/plugins/variadic/tests/known/oracle/swprintf.res.oracle
@@ -54,6 +54,7 @@
   __retres ∈ {0}
 /* Generated by Frama-C */
 #include "errno.h"
+#include "signal.h"
 #include "stdarg.h"
 #include "stdio.h"
 #include "time.h"
diff --git a/src/plugins/variadic/tests/known/oracle/wchar.res.oracle b/src/plugins/variadic/tests/known/oracle/wchar.res.oracle
index 0f8d049bfce33a5a0d3672e0ca5738d642229c0a..6d0225a773070bb675e09debc3d519189cff1cc1 100644
--- a/src/plugins/variadic/tests/known/oracle/wchar.res.oracle
+++ b/src/plugins/variadic/tests/known/oracle/wchar.res.oracle
@@ -83,6 +83,7 @@
   S___fc_stdout[0..1] ∈ [--..--]
 /* Generated by Frama-C */
 #include "errno.h"
+#include "signal.h"
 #include "stdarg.h"
 #include "stdio.h"
 #include "time.h"
diff --git a/tests/libc/oracle/fc_libc.0.res.oracle b/tests/libc/oracle/fc_libc.0.res.oracle
index eab1d99264c45d6300692246cc0ac9ef6fca48d0..ba81dc3d6039cf8489dcec07f828cb488595f2b3 100644
--- a/tests/libc/oracle/fc_libc.0.res.oracle
+++ b/tests/libc/oracle/fc_libc.0.res.oracle
@@ -156,12 +156,12 @@
    wcstombs (0 call); wctomb (0 call); wmemchr (0 call); wmemcmp (0 call);
    wmemmove (0 call); write (0 call); 
   
-  'Extern' global variables (17)
+  'Extern' global variables (15)
   ==============================
-   __fc_basename; __fc_dirname; __fc_getpwuid_pw_dir; __fc_getpwuid_pw_gid;
-   __fc_getpwuid_pw_name; __fc_getpwuid_pw_passwd; __fc_getpwuid_pw_shell;
-   __fc_getpwuid_pw_uid; __fc_hostname; __fc_mblen_state; __fc_mbtowc_state;
-   __fc_ttyname; __fc_wctomb_state; optarg; opterr; optopt; tzname
+   __fc_basename; __fc_dirname; __fc_getpwuid_pw_dir; __fc_getpwuid_pw_name;
+   __fc_getpwuid_pw_passwd; __fc_getpwuid_pw_shell; __fc_hostname;
+   __fc_mblen_state; __fc_mbtowc_state; __fc_ttyname; __fc_wctomb_state;
+   optarg; opterr; optopt; tzname
   
   Potential entry points (1)
   ==========================
@@ -171,7 +171,7 @@
   ============== 
   Sloc = 1083
   Decision point = 204
-  Global variables = 68
+  Global variables = 66
   If = 195
   Loop = 43
   Goto = 89
diff --git a/tests/libc/oracle/fc_libc.1.res.oracle b/tests/libc/oracle/fc_libc.1.res.oracle
index a0d63cf77b129c701a89d1e3da29808ad515ff32..c0bb6e199f8b77143bc6427264ab126e5e3480cc 100644
--- a/tests/libc/oracle/fc_libc.1.res.oracle
+++ b/tests/libc/oracle/fc_libc.1.res.oracle
@@ -7050,10 +7050,6 @@ extern char __fc_getpwuid_pw_name[64];
 
 extern char __fc_getpwuid_pw_passwd[64];
 
-extern uid_t __fc_getpwuid_pw_uid;
-
-extern gid_t __fc_getpwuid_pw_gid;
-
 extern char __fc_getpwuid_pw_dir[64];
 
 extern char __fc_getpwuid_pw_shell[64];
@@ -7061,8 +7057,8 @@ extern char __fc_getpwuid_pw_shell[64];
 struct passwd __fc_pwd =
   {.pw_name = __fc_getpwuid_pw_name,
    .pw_passwd = __fc_getpwuid_pw_passwd,
-   .pw_uid = __fc_getpwuid_pw_uid,
-   .pw_gid = __fc_getpwuid_pw_gid,
+   .pw_uid = 0U,
+   .pw_gid = 0U,
    .pw_gecos = (char *)0,
    .pw_dir = __fc_getpwuid_pw_dir,
    .pw_shell = __fc_getpwuid_pw_shell};