arm: Add missing it instructions

When building in thumb mode, the conditional instructions are supposed
to have 'it' instructions preceding them (unless the assembler is
set to automatically inject such).

This fixes building with clang/llvm 3.9, while the build passed
with clang/llvm 3.8 (unsure whether it actually injected such instructions
though).

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/math/copysignl.S

diff --git a/mingw-w64-crt/math/copysignl.S b/mingw-w64-crt/math/copysignl.S
index 77237e9..0becf53 100644
--- a/mingw-w64-crt/math/copysignl.S
+++ b/mingw-w64-crt/math/copysignl.S
@@ -38,10 +38,12 @@
 	bmi	1f /* jump if d1 is negative */
 	fcmpzd	d0
 	fmstat
+	it mi
 	vnegmi.f64	d0, d0 /* negate d0 if it is negative */
 	bx	lr
 	1: fcmpzd	d0
 	fmstat
+	it pl
 	vnegpl.f64	d0, d0 /* negate d0 if it is positive */
 	bx	lr
 #elif defined(_X86_) || defined(__i386__)