diff --git a/src/lib/libast/comp/conf.sh b/src/lib/libast/comp/conf.sh
index 9d0841154..7b4bb500d 100644
--- a/src/lib/libast/comp/conf.sh
+++ b/src/lib/libast/comp/conf.sh
@@ -144,7 +144,7 @@ main()
 	return 1;
 #else
 	_ast_intmax_t		s = 0x7fffffffffffffffLL;
-	unsigned _ast_intmax_t	u = 0xffffffffffffffffLL;
+	unsigned _ast_intmax_t	u = 0xffffffffffffffffULL;
 
 	return 0;
 #endif
@@ -817,7 +817,11 @@ defined() # list-file
 			cat <<!
 ${head}
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 #undef conf
@@ -845,7 +849,11 @@ unsigned int conf[] = {
 		cat <<!
 ${head}
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 #undef conf
@@ -886,7 +894,11 @@ done
 	cat <<!
 ${head}
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 #undef conf
@@ -1064,7 +1076,7 @@ do	eval name=\"'$'CONF_name_$key\"
 	case $flags in
 	*[Ll]*)	d=
 		case ${conf_name} in
-		LONG_MAX|SSIZE_MAX)
+		LONG_MAX|UINT_MAX|INT_MAX|SHRT_MAX|SSIZE_MAX|WORD_BIT|LONG_BIT|PTHREAD_*)
 			x=
 			;;
 		*)	eval x='$'CONF_const_${conf_name}
@@ -1124,7 +1136,11 @@ do	eval name=\"'$'CONF_name_$key\"
 ${head}
 #include <stdio.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 int
@@ -1139,7 +1155,11 @@ main()
 ${head}
 #include <stdio.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 ${script}
@@ -1286,7 +1306,11 @@ printf("#endif\n");
 				*)	cat > $tmp.c <<!
 ${head}
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 ${script}
@@ -1365,7 +1389,7 @@ ${script}
 		*[lLuU])
 			case $LL_suffix in
 			??)	case $conf_limit in
-				*[!lL][lL]|*[!lL][lL][uU])
+				*[0-9a-fA-F][lL]|*[0-9a-fA-F][uU][lL])
 					conf_limit=${conf_limit}L
 					;;
 				esac
@@ -1400,7 +1424,7 @@ ${script}
 		*[lLuU])
 			case $LL_suffix in
 			??)	case $conf_minmax in
-				*[!lL][lL]|*[!lL][lL][uU])
+				*[0-9a-fA-F][lL]|*[0-9a-fA-F][uU][lL])
 					conf_minmax=${conf_minmax}L
 					;;
 				esac
@@ -1577,7 +1601,11 @@ esac
 cat <<!
 ${head}
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <limits.h>
+#if defined(__linux__)
+#include <linux/limits.h>
+#endif
 #include <unistd.h>$systeminfo$headers
 ${tail}
 #include "${base}.h"