make SQRT_MINUS_ONE not static

src/per_field/f_field.tmpl.h

@@ -80,9 +80,7 @@ mask_t gf_deserialize (gf x, const uint8_t serial[SER_BYTES],int with_highbit);
 
 #define P_MOD_8 $(modulus % 8)
 #if P_MOD_8 == 5
-    static const gf SQRT_MINUS_ONE = {FIELD_LITERAL( /* TODO make not static */
-        $(ser(msqrt(-1,modulus),gf_lit_limb_bits) if modulus % 4 == 1 else "/* NOPE */")
-    )};
+    extern const gf SQRT_MINUS_ONE;
 #endif
 
 #ifndef LIMBPERM

src/per_field/f_generic.tmpl.c

@@ -1,18 +1,16 @@
-/**
- * @cond internal
- * @file per_field.c
- * @copyright
- *   Copyright (c) 2015-2016 Cryptography Research, Inc.  \n
- *   Released under the MIT License.  See LICENSE.txt for license information.
- * @author Mike Hamburg
- * @brief Generic arithmetic which has to be compiled per field.
- */
+/** @brief Generic arithmetic which has to be compiled per field. */
 
 #include "field.h"
 
 static const gf MODULUS = {FIELD_LITERAL(
     $(ser(modulus,gf_lit_limb_bits))
 )};
+    
+#if P_MOD_8 == 5
+    const gf SQRT_MINUS_ONE = {FIELD_LITERAL(
+        $(ser(msqrt(-1,modulus),gf_lit_limb_bits) if modulus % 4 == 1 else "/* NOPE */")
+    )};
+#endif
 
 /** Serialize to wire format. */
 void gf_serialize (uint8_t serial[SER_BYTES], const gf x, int with_hibit) {