test/bench/shoutout: fix compliation

-lm must come after the source file, versions of gcc insist this strict order.
On standard compliant systems, we no longer need malloc.h for malloc.
Use pkg-config(1) to get correct glib cflags and libs.
Fix compiler warning in threadring.c and k-nucleotide.c.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6198076

test/bench/shootout/binary-tree.c

@@ -36,7 +36,6 @@ POSSIBILITY OF SUCH DAMAGE.
        icc -O3 -ip -unroll -static binary-trees.c -lm
 */
 
-#include <malloc.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

test/bench/shootout/k-nucleotide.c

@@ -221,7 +221,7 @@ main ()
 
    free(s);
 
-   g_ptr_array_foreach(roots, free, NULL);
+   g_ptr_array_foreach(roots, (GFunc)free, NULL);
    g_ptr_array_free(roots, TRUE);
 
    return 0;

test/bench/shootout/threadring.c

@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE.
 * contributed by Premysl Hruby
 */
 
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <pthread.h>
@@ -57,7 +58,7 @@ static struct stack stacks[THREADS];
 
 static void* thread(void *num)
 {
-   int l = (int)num;
+   int l = (int)(uintptr_t)num;
    int r = (l+1) % THREADS;
    int token;
 
@@ -94,7 +95,7 @@ int main(int argc, char **argv)
       pthread_mutex_lock(mutex + i);
 
       pthread_attr_setstack(&stack_attr, &stacks[i], sizeof(struct stack));
-      pthread_create(&cthread, &stack_attr, thread, (void*)i);
+      pthread_create(&cthread, &stack_attr, thread, (void*)(uintptr_t)i);
    }
 
    pthread_mutex_unlock(mutex + 0);

test/bench/shootout/timing.sh

@@ -97,7 +97,7 @@ revcomp() {
 
 nbody() {
 	runonly echo 'nbody -n 50000000'
-	run 'gcc -O2 -lm nbody.c' a.out 50000000
+	run 'gcc -O2 nbody.c -lm' a.out 50000000
 	run 'gccgo -O2 nbody.go' a.out -n 50000000
 	run 'gc nbody' $O.out -n 50000000
 	run 'gc_B nbody' $O.out -n 50000000
@@ -147,7 +147,7 @@ knucleotide() {
 	runonly gcc -O2 fasta.c
 	runonly a.out 1000000 > x  # should be using 25000000
 	runonly echo 'k-nucleotide 1000000'
-	run 'gcc -O2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include k-nucleotide.c -lglib-2.0' a.out <x
+	run "gcc -O2 k-nucleotide.c $(pkg-config glib-2.0 --cflags --libs)" a.out <x
 	run 'gccgo -O2 k-nucleotide.go' a.out <x
 	run 'gccgo -O2 k-nucleotide-parallel.go' a.out <x
 	run 'gc k-nucleotide' $O.out <x