ninja: Specifically implement gcc rspfile style quoting

This differs from sh-quoting in that a backslash *always* escapes the
following character, even inside single quotes.  Yes, really.

https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libiberty/argv.c#l176

mesonbuild/backend/ninjabackend.py

@@ -65,6 +65,16 @@ def cmd_quote(s):
 
     return s
 
+def gcc_rsp_quote(s):
+    # see: the function buildargv() in libiberty
+    #
+    # this differs from sh-quoting in that a backslash *always* escapes the
+    # following character, even inside single quotes.
+
+    s = s.replace('\\', '\\\\')
+
+    return shlex.quote(s)
+
 # How ninja executes command lines differs between Unix and Windows
 # (see https://ninja-build.org/manual.html#ref_rule_command)
 if mesonlib.is_windows():
@@ -134,7 +144,7 @@ class NinjaComment:
 class NinjaRule:
     def __init__(self, rule, command, args, description,
                  rspable = False, deps = None, depfile = None, extra = None,
-                 rspfile_quote_style = 'sh'):
+                 rspfile_quote_style = 'gcc'):
 
         def strToCommandArg(c):
             if isinstance(c, NinjaCommandArg):
@@ -168,7 +178,7 @@ class NinjaRule:
         self.rspable = rspable  # if a rspfile can be used
         self.refcount = 0
         self.rsprefcount = 0
-        self.rspfile_quote_style = rspfile_quote_style  # rspfile quoting style is 'sh' or 'cl'
+        self.rspfile_quote_style = rspfile_quote_style  # rspfile quoting style is 'gcc' or 'cl'
 
     @staticmethod
     def _quoter(x, qf = quote_func):
@@ -186,7 +196,7 @@ class NinjaRule:
         if self.rspfile_quote_style == 'cl':
             rspfile_quote_func = cmd_quote
         else:
-            rspfile_quote_func = shlex.quote
+            rspfile_quote_func = gcc_rsp_quote
 
         def rule_iter():
             if self.refcount:
@@ -334,7 +344,7 @@ class NinjaBuildElement:
             if self.rule.rspfile_quote_style == 'cl':
                 qf = cmd_quote
             else:
-                qf = shlex.quote
+                qf = gcc_rsp_quote
         else:
             qf = quote_func
 
@@ -1725,7 +1735,7 @@ int dummy;
                 pool = None
             self.add_rule(NinjaRule(rule, cmdlist, args, description,
                                     rspable=static_linker.can_linker_accept_rsp(),
-                                    rspfile_quote_style='cl' if isinstance(static_linker, VisualStudioLinker) else 'sh',
+                                    rspfile_quote_style='cl' if isinstance(static_linker, VisualStudioLinker) else 'gcc',
                                     extra=pool))
 
     def generate_dynamic_link_rules(self):
@@ -1749,7 +1759,7 @@ int dummy;
                 self.add_rule(NinjaRule(rule, command, args, description,
                                         rspable=compiler.can_linker_accept_rsp(),
                                         rspfile_quote_style='cl' if (compiler.get_argument_syntax() == 'msvc' or
-                                                                     isinstance(compiler, DmdDCompiler)) else 'sh',
+                                                                     isinstance(compiler, DmdDCompiler)) else 'gcc',
                                         extra=pool))
 
         args = self.environment.get_build_command() + \
@@ -1778,7 +1788,7 @@ int dummy;
         description = 'Compiling C Sharp target $out'
         self.add_rule(NinjaRule(rule, command, args, description,
                                 rspable=mesonlib.is_windows(),
-                                rspfile_quote_style='cl' if isinstance(compiler, VisualStudioCsCompiler) else 'sh'))
+                                rspfile_quote_style='cl' if isinstance(compiler, VisualStudioCsCompiler) else 'gcc'))
 
     def generate_vala_compile_rules(self, compiler):
         rule = self.compiler_to_rule_name(compiler)
@@ -1865,7 +1875,7 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         self.add_rule(NinjaRule(rule, command, args, description,
                                 rspable=compiler.can_linker_accept_rsp(),
                                 rspfile_quote_style='cl' if (compiler.get_argument_syntax() == 'msvc' or
-                                                             isinstance(compiler, DmdDCompiler)) else 'sh',
+                                                             isinstance(compiler, DmdDCompiler)) else 'gcc',
                                 deps=deps, depfile=depfile))
 
     def generate_pch_rule_for(self, langname, compiler):