Ddd an "Defaults" section to the ini file (#1071)

After reading the "WinMerge" section try to read the "Defaults" section.
Overwrite existing entries in "iniFileKeyValues" with the ones from the "Defaults" section.
This section is not written to, as it should contain default entries, that are reverted at each restart of WinMerge.
More informations see #460.

Src/Common/IniOptionsMgr.cpp

@@ -12,6 +12,7 @@
 #include "OptionsMgr.h"
 
 LPCWSTR lpAppName = TEXT("WinMerge");
+LPCWSTR lpDefaultSection = TEXT("Defaults");
 
 struct AsyncWriterThreadParams
 {
@@ -86,6 +87,25 @@ std::map<String, String> CIniOptionsMgr::Load(const String& iniFilePath)
 			p = v + vlen + 1;
 		}
 	}
+
+	// after reading the "WinMerge" section try to read the "Defaults" section; overwrite existing entries in "iniFileKeyValues" with the ones from the "Defaults" section
+	if (GetPrivateProfileSection(lpDefaultSection, str.data(), static_cast<DWORD>(str.size()), iniFilePath.c_str()) > 0)
+	{
+		TCHAR* p = str.data();
+		while (*p)
+		{
+			TCHAR* v = _tcschr(p, '=');
+			if (!v)
+				break;
+			++v;
+			size_t vlen = _tcslen(v);
+			String value{ v, v + vlen };
+			String key{ p, v - 1 };
+			iniFileKeyValues.insert_or_assign(key, UnescapeValue(value));
+			p = v + vlen + 1;
+		}
+	}
+
 	return iniFileKeyValues;
 }