hadrian: disable PIC for in-tree GMP on wasm32

This patch disables PIC for in-tree GMP on wasm32 target. Enabling PIC
unconditionally adds undesired code size and runtime overhead for
wasm32.

(cherry picked from commit f9c1ae12)
(cherry picked from commit 5f728fc4)
(cherry picked from commit f45b02a8)

hadrian/src/Settings/Builders/Configure.hs

@@ -14,7 +14,6 @@ configureBuilderArgs = do
                 targetPlatform <- getSetting TargetPlatform
                 buildPlatform <- getSetting BuildPlatform
                 pure $ [ "--enable-shared=no"
-                     , "--with-pic=yes"
                      , "--host=" ++ targetPlatform    -- GMP's host is our target
                      , "--build=" ++ buildPlatform ]
                      -- Disable GMP's alloca usage on wasm32, it may
@@ -24,6 +23,10 @@ configureBuilderArgs = do
                      -- more detailed explanation of this configure
                      -- option.
                      <> [ "--enable-alloca=malloc-reentrant" | targetArch == "wasm32" ]
+                     -- Enable PIC unless target is wasm32, in which
+                     -- case we don't want libgmp.a to be bloated due
+                     -- to PIC overhead.
+                     <> [ "--with-pic=yes" | targetArch /= "wasm32" ]
 
             , builder (Configure libffiPath) ? do
                 top            <- expr topDirectory