fix clang 3.4 warnings and ignore uninteresting ones

fixed warnings:
src/cmd/fossil/disk.c:37:14: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
src/cmd/fossil/disk.c:38:14: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
src/cmd/fossil/disk.c:39:14: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
src/cmd/fossil/disk.c:40:13: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
src/cmd/fossil/disk.c:41:14: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
src/libndb/ndbreorder.c:41:55: warning: for loop has empty body [-Wempty-body]

ignored warnings:
src/cmd/acid/dbg.y:393:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/bc.y:1327:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/bc.y:1327:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/grep/grep.y:420:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/grep/grep.y:420:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/hoc/hoc.y:692:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/hoc/hoc.y:692:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/lex/parser.y:886:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/rc/syn.y:303:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/cmd/units.y:1003:9: warning: array index -1 is before the beginning of the array [-Warray-bounds]
src/libregexp/regcomp.c:19:16: warning: variable 'reprog' is not needed and will not be emitted [-Wunneeded-internal-declaration]

LGTM=rsc
R=rsc
https://codereview.appspot.com/158250043

bin/9c

@@ -67,6 +67,8 @@ useclang()
 		-Wno-unused-value \
 		-Wno-array-bounds \
 		-Wno-gnu-designator \
+		-Wno-array-bounds \
+		-Wno-unneeded-internal-declaration \
 		-fsigned-char \
 		-fno-caret-diagnostics \
 	"

src/cmd/fossil/disk.c

@@ -34,11 +34,11 @@ struct Disk {
 
 /* keep in sync with Part* enum in dat.h */
 static char *partname[] = {
-	[PartError]	"error",
-	[PartSuper]	"super",
-	[PartLabel]	"label",
-	[PartData]	"data",
-	[PartVenti]	"venti",
+	[PartError]	= "error",
+	[PartSuper]	= "super",
+	[PartLabel]	= "label",
+	[PartData]	= "data",
+	[PartVenti]	= "venti",
 };
 
 Disk *

src/libndb/ndbreorder.c

@@ -38,7 +38,7 @@ ndbreorder(Ndbtuple *t, Ndbtuple *x)
 	if(x != last->line){
 
 		/* find entry before x */
-		for(prev = last; prev->line != x; prev = prev->line);
+		for(prev = last; prev->line != x; prev = prev->line)
 			;
 
 		/* detach line */