Use cc(1)'s __has_include() instead of build-system checks

configure.ac

@@ -36,13 +36,6 @@ LT_LIB_DLLOAD
 
 dnl Checks for libraries.
 
-dnl Checks for header files.
-AC_CHECK_HEADERS(crypt.h utmp.h \
-	termio.h sgtty.h sys/ioctl.h paths.h \
-	sys/capability.h sys/random.h \
-	gshadow.h lastlog.h rpc/key_prot.h acl/libacl.h \
-	attr/libattr.h attr/error_context.h)
-
 dnl shadow now uses the libc's shadow implementation
 AC_CHECK_HEADER([shadow.h],,[AC_MSG_ERROR([You need a libc with shadow.h])])
 

lib/csrand.c

@@ -10,8 +10,8 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <unistd.h>
-#if HAVE_SYS_RANDOM_H
-#include <sys/random.h>
+#if __has_include(<sys/random.h>)
+# include <sys/random.h>
 #endif
 
 #include "bit.h"

lib/defines.h

@@ -41,7 +41,7 @@
  * crypt(3), crypt_gensalt(3), and their
  * feature test macros may be defined in here.
  */
-#if HAVE_CRYPT_H
+#if __has_include(<crypt.h>)
 # include <crypt.h>
 #endif
 

lib/gshadow.c

@@ -9,7 +9,7 @@
 
 #include <config.h>
 
-#if defined(SHADOWGRP) && !defined(HAVE_GSHADOW_H)
+#if defined(SHADOWGRP) && !__has_include(<gshadow.h>)
 
 #ident "$Id$"
 

lib/gshadow_.h

@@ -9,7 +9,7 @@
 #define SHADOW_INCLUDE_LIB_GSHADOW__H_
 
 
-#if defined(HAVE_GSHADOW_H)
+#if __has_include(<gshadow.h>)
 # include <gshadow.h>
 #else
 
@@ -41,5 +41,5 @@ int putsgent (const struct sgrp *, FILE *);
 #define	GSHADOW	"/etc/gshadow"
 
 
-#endif  // !HAVE_GSHADOW_H
+#endif  // !__has_include(<gshadow.h>)
 #endif  // include guard

lib/idmapping.c

@@ -12,9 +12,9 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <strings.h>
-#if HAVE_SYS_CAPABILITY_H
 #include <sys/prctl.h>
-#include <sys/capability.h>
+#if __has_include(<sys/capability.h>)
+# include <sys/capability.h>
 #endif
 
 #include "alloc/calloc.h"
@@ -86,7 +86,7 @@ get_map_ranges(int ranges, int argc, char **argv)
  */
 #define ULONG_DIGITS (((WIDTHOF(unsigned long) + 9)/10)*3)
 
-#if HAVE_SYS_CAPABILITY_H
+#if __has_include(<sys/capability.h>)
 static inline bool maps_lower_root(int cap, int ranges, const struct map_range *mappings)
 {
 	int idx;
@@ -129,7 +129,7 @@ void write_mapping(int proc_dir_fd, int ranges, const struct map_range *mappings
 	char *buf, *pos, *end;
 	int fd;
 
-#if HAVE_SYS_CAPABILITY_H
+#if __has_include(<sys/capability.h>)
 	int cap;
 	struct __user_cap_header_struct hdr = {_LINUX_CAPABILITY_VERSION_3, 0};
 	struct __user_cap_data_struct data[2] = {{0}};

lib/pam_defs.h

@@ -6,11 +6,12 @@
  */
 
 #include <config.h>
+
 #include <security/pam_appl.h>
-#ifdef HAVE_SECURITY_PAM_MISC_H
+#if __has_include(<security/pam_misc.h>)
 # include <security/pam_misc.h>
 #endif
-#ifdef HAVE_SECURITY_OPENPAM_H
+#if __has_include(<security/openpam.h>)
 # include <security/openpam.h>
 #endif