Fix Clang warnings on Windows

- Align DLLEXPORT in definitions and declations. There is still a few
  cases left, where the declation in the compiler's complex.h disagrees
  with the implementation here. For now we can't do anything about that,
  but maybe should be revisited in the future.
- Fix the syntax on an .ascii directive that gcc accepted mistakingly, but
  clang does not.

Author: Keno

amd64/bsd_asm.h

@@ -76,7 +76,7 @@
 #define _START_ENTRY_WIN .code; _START_ENTRY
 #endif
 #define _ENTRY(x)	_START_ENTRY_WIN; \
-            .globl CNAME(x); .section .drectve; .ascii " -export:" #x; \
+            .globl CNAME(x); .section .drectve; .ascii " -export:", #x; \
             .section .text; .def CNAME(x); .scl 2; .type 32; .endef; CNAME(x):
 #endif
 

include/openlibm_fenv_amd64.h

@@ -125,8 +125,8 @@ fegetexceptflag(fexcept_t *__flagp, int __excepts)
 	return (0);
 }
 
-int fesetexceptflag(const fexcept_t *__flagp, int __excepts);
-int feraiseexcept(int __excepts);
+DLLEXPORT int fesetexceptflag(const fexcept_t *__flagp, int __excepts);
+DLLEXPORT int feraiseexcept(int __excepts);
 
 __fenv_static __attribute__((always_inline)) inline int
 fetestexcept(int __excepts)
@@ -176,8 +176,8 @@ fesetround(int __round)
 	return (0);
 }
 
-int fegetenv(fenv_t *__envp);
-int feholdexcept(fenv_t *__envp);
+DLLEXPORT int fegetenv(fenv_t *__envp);
+DLLEXPORT int feholdexcept(fenv_t *__envp);
 
 __fenv_static inline int
 fesetenv(const fenv_t *__envp)
@@ -196,12 +196,12 @@ fesetenv(const fenv_t *__envp)
 	return (0);
 }
 
-int feupdateenv(const fenv_t *__envp);
+DLLEXPORT int feupdateenv(const fenv_t *__envp);
 
 #if __BSD_VISIBLE
 
-int feenableexcept(int __mask);
-int fedisableexcept(int __mask);
+DLLEXPORT int feenableexcept(int __mask);
+DLLEXPORT int fedisableexcept(int __mask);
 
 /* We currently provide no external definition of fegetexcept(). */
 static inline int