std.math.egcd: Skip large integer tests for C backend

Author: jedisct1

lib/std/math/egcd.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 
 /// Result of the Extended Euclidean Algorithm containing the GCD and Bézout coefficients.
 /// For inputs a and b, returns gcd, x, y such that: a*x + b*y = gcd
@@ -196,6 +197,7 @@ test "u64 very large values" {
 }
 
 test "u128 values" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     const a: u128 = 123456789012345678901234567890;
     const b: u128 = 987654321098765432109876543210;
     const result = egcd(a, b);
@@ -311,6 +313,7 @@ test "modular inverse use case" {
     try std.testing.expectEqual(@as(u64, 1), verify);
 }
 test "u256 type" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     const a: u256 = 123456789012345678901234567890123456789012345678901234567890;
     const b: u256 = 987654321098765432109876543210987654321098765432109876543210;
     const result = egcd(a, b);
@@ -324,6 +327,7 @@ test "u256 type" {
 }
 
 test "u512 type" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     const a: u512 = 999999999999999999;
     const b: u512 = 888888888888888888;
     const result = egcd(a, b);
@@ -334,6 +338,7 @@ test "u512 type" {
 }
 
 test "i256 type" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     const a: i256 = -123456789012345678901234567890;
     const b: i256 = 987654321098765432109876543210;
     const result = egcd(a, b);
@@ -347,6 +352,7 @@ test "i256 type" {
 }
 
 test "u1024 type" {
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     // Test that very large types compile and work
     const a: u1024 = 12345678901234567890;
     const b: u1024 = 9876543210987654321;
@@ -358,6 +364,8 @@ test "u1024 type" {
 }
 
 test "u4096" {
+    if (true) return error.SkipZigTest; // Codegen error on some platforms
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: C backend missing big integer helpers
     const a: u4096 = 100;
     const b: u4096 = 50;
     const result = egcd(a, b);