numa: parenthesise the page-align arithmetic (#313)

`(uintptr_t)p+n+4095 & ~(uintptr_t)4095` is CORRECT — `+` binds tighter than
`&` in C, so the rounding happens before the mask, which is what was meant.
But gcc -Wall warns (`suggest parentheses around '+' in operand of '&'`), and
this repo builds clean at -Wall -Wextra. Warning-free is a property worth more
than the two characters it costs to keep: it is what makes a NEW warning
visible instead of scrolling past in a wall of noise.

No behaviour change; the emitted code is identical.

Co-Authored-By: ZacharyZcR <#313>

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

c/glm.c

@@ -1178,7 +1178,7 @@ static void numa_slab_bind(void *p, size_t n){
     if(g_numa_nodes<2 || !p || !n) return;
     unsigned long mask=(1UL<<g_numa_nodes)-1;
     uintptr_t a=(uintptr_t)p & ~(uintptr_t)4095;
-    size_t len=((uintptr_t)p+n+4095 & ~(uintptr_t)4095) - a;
+    size_t len=(((uintptr_t)p+n+4095) & ~(uintptr_t)4095) - a;
     syscall(SYS_mbind,a,len,3/*MPOL_INTERLEAVE*/,&mask,
             (unsigned long)(g_numa_nodes+1),(unsigned)2/*MPOL_MF_MOVE*/);
 #else