fix issues from public functions defined without declaration visible

policy is that all public functions which have a public declaration
should be defined in a context where that public declaration is
visible, to avoid preventable type mismatches.

an audit performed using GCC's -Wmissing-declarations turned up the
violations corrected here. in some cases the public header had not
been included; in others, a feature test macro needed to make the
declaration visible had been omitted.

in the case of gethostent and getnetent, the omission seems to have
been intentional, as a hack to admit a single stub definition for both
functions. this kind of hack is no longer acceptable; it's UB and
would not fly with LTO or advanced toolchains. the hack is undone to
make exposure of the declarations possible.

3 files changed, 5 insertions, 0 deletions

diff --git a/src/misc/getentropy.c b/src/misc/getentropy.c
index 4c61ae26..d2f282ce 100644
--- a/src/misc/getentropy.c
+++ b/src/misc/getentropy.c
@@ -1,3 +1,5 @@
+#define _BSD_SOURCE
+#include <unistd.h>
 #include <sys/random.h>
 #include <pthread.h>
 #include <errno.h>
diff --git a/src/misc/issetugid.c b/src/misc/issetugid.c
index 6ffd9300..ddc2ca0e 100644
--- a/src/misc/issetugid.c
+++ b/src/misc/issetugid.c
@@ -1,3 +1,4 @@
+#define _BSD_SOURCE
 #include <unistd.h>
 #include "libc.h"
 
diff --git a/src/misc/syscall.c b/src/misc/syscall.c
index 9d435a97..6f3ef656 100644
--- a/src/misc/syscall.c
+++ b/src/misc/syscall.c
@@ -1,3 +1,5 @@
+#define _BSD_SOURCE
+#include <unistd.h>
 #include "syscall.h"
 #include <stdarg.h>