do initial work to enable preproc processing

tools/preproc/Makefile

@@ -1,6 +1,6 @@
 CXX := g++
 
-CXXFLAGS := -std=c++11 -O2 -s -Wall -Wno-switch -Werror
+CXXFLAGS := -std=c++11 -O3 -Wall -Wno-switch -Werror
 
 SRCS := asm_file.cpp c_file.cpp charmap.cpp preproc.cpp string_parser.cpp \
 	utf8.cpp

tools/preproc/asm_file.cpp

@@ -476,11 +476,9 @@ void AsmFile::ExpectEmptyRestOfLine()
         m_lineStart = m_pos;
         m_lineNum++;
     }
-    else if (m_buffer[m_pos] == '\r' && m_buffer[m_pos + 1] == '\n')
+    else if (m_buffer[m_pos] == '\r')
     {
-        m_pos += 2;
-        m_lineStart = m_pos;
-        m_lineNum++;
+        RaiseError("only Unix-style LF newlines are supported");
     }
     else
     {

tools/preproc/charmap.cpp

@@ -67,6 +67,14 @@ private:
 
 CharmapReader::CharmapReader(std::string filename) : m_filename(filename)
 {
+    if (filename == "")
+    {
+        m_size = 0;
+        m_pos = 0;
+        m_buffer = new char[1] {};
+        return;
+    }
+
     FILE *fp = std::fopen(filename.c_str(), "rb");
 
     if (fp == NULL)

tools/preproc/preproc.cpp

@@ -132,30 +132,27 @@ char* GetFileExtension(char* filename)
 
 int main(int argc, char **argv)
 {
-    if (argc != 3)
+    if (argc != 3 && argc != 2)
     {
         std::fprintf(stderr, "Usage: %s SRC_FILE CHARMAP_FILE", argv[0]);
         return 1;
     }
 
-    g_charmap = new Charmap(argv[2]);
+    g_charmap = new (std::nothrow) Charmap(argc == 3 ? argv[2] : "");
+    if (!g_charmap)
+        FATAL_ERROR("Failed to allocate space for Charmap.\n");
 
-    if (argv[1][0] == '-' && argv[1][1] == 0) {
-        PreprocCFile("-");
-    } else {
-        char* extension = GetFileExtension(argv[1]);
+    char* extension = GetFileExtension(argv[1]);
 
-        if (!extension)
-            FATAL_ERROR("\"%s\" has no file extension.\n", argv[1]);
-
-        if ((extension[0] == 's') && extension[1] == 0)
-            PreprocAsmFile(argv[1]);
-        else if ((extension[0] == 'c' || extension[0] == 'i') && extension[1] == 0)
-            PreprocCFile(argv[1]);
-        else
-            FATAL_ERROR("\"%s\" has an unknown file extension of \"%s\".\n", argv[1], extension);
-    }
+    if (!extension)
+        FATAL_ERROR("\"%s\" has no file extension.\n", argv[1]);
 
+    if ((extension[0] == 's') && extension[1] == 0)
+        PreprocAsmFile(argv[1]);
+    else if ((extension[0] == 'c' || extension[0] == 'i') && extension[1] == 0)
+        PreprocCFile(argv[1]);
+    else
+        FATAL_ERROR("\"%s\" has an unknown file extension of \"%s\".\n", argv[1], extension);
 
     return 0;
 }