Clean up tidy scripts, coverage, performance

This restructures tidy.py to walk the tree itself,
and improves performance considerably by not loading entire
files into buffers for licenseck.

Splits build rules into 'tidy', 'tidy-basic', 'tidy-binaries',
'tidy-errors', 'tidy-features'.

src/test/run-make/c-dynamic-dylib/cfoo.c

@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }

src/test/run-make/c-dynamic-rlib/cfoo.c

@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }

src/test/run-make/c-link-to-rust-dylib/bar.c

@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {

src/test/run-make/c-link-to-rust-staticlib/bar.c

@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {

src/test/run-make/c-static-dylib/cfoo.c

@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }

src/test/run-make/c-static-rlib/cfoo.c

@@ -1 +1,2 @@
+// ignore-license
 int foo() { return 0; }

src/test/run-make/extern-fn-generic/test.c

@@ -1,16 +1,17 @@
+// ignore-license
 #include <stdint.h>
 
 typedef struct TestStruct {
-	uint8_t x;
-	int32_t y;
+        uint8_t x;
+        int32_t y;
 } TestStruct;
 
 typedef int callback(TestStruct s);
 
 uint32_t call(callback *c) {
-	TestStruct s;
-	s.x = 'a';
-	s.y = 3;
+        TestStruct s;
+        s.x = 'a';
+        s.y = 3;
 
-	return c(s);
+        return c(s);
 }

src/test/run-make/extern-fn-mangle/test.c

@@ -1,8 +1,9 @@
+// ignore-license
 #include <stdint.h>
 
 uint32_t foo();
 uint32_t bar();
 
 uint32_t add() {
-	return foo() + bar();
+        return foo() + bar();
 }

src/test/run-make/extern-fn-with-packed-struct/test.c

@@ -1,3 +1,4 @@
+// ignore-license
 // Pragma needed cause of gcc bug on windows: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52991
 #pragma pack(1)
 struct __attribute__((packed)) Foo {

src/test/run-make/extern-fn-with-union/test.c

@@ -1,3 +1,4 @@
+// ignore-license
 #include <stdio.h>
 #include <stdint.h>
 

src/test/run-make/interdependent-c-libraries/bar.c

@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 void bar() { foo(); }

src/test/run-make/interdependent-c-libraries/foo.c

@@ -1 +1,2 @@
+// ignore-license
 void foo() {}

src/test/run-make/issue-12446/foo.c

@@ -1 +1,2 @@
+// ignore-license
 void some_c_symbol() {}

src/test/run-make/issue-15460/foo.c

@@ -1 +1,2 @@
+// ignore-license
 void foo() {}

src/test/run-make/link-path-order/correct.c

@@ -1 +1,2 @@
+// ignore-license
 int should_return_one() { return 1; }

src/test/run-make/link-path-order/wrong.c

@@ -1 +1,2 @@
+// ignore-license
 int should_return_one() { return 0; }

src/test/run-make/linkage-attr-on-static/foo.c

@@ -1,3 +1,4 @@
+// ignore-license
 #include <stdint.h>
 
 extern int32_t BAZ;

src/test/run-make/lto-smoke-c/bar.c

@@ -1,3 +1,4 @@
+// ignore-license
 void foo();
 
 int main() {

src/test/run-make/manual-link/bar.c

@@ -1 +1,2 @@
+// ignore-license
 void bar() {}

src/test/run-make/manual-link/foo.c

@@ -1 +1,2 @@
+// ignore-license
 void bar() {}

src/test/run-make/no-duplicate-libs/bar.c

@@ -1,3 +1,4 @@
+// ignore-license
 extern void foo();
 
 void bar() { foo(); }

src/test/run-make/no-duplicate-libs/foo.c

@@ -1 +1,2 @@
+// ignore-license
 void foo() {}