remove warnings about uninitialized variables

[WalterBright]

Fixes these spurious warnings:

mtype.c: In member function 'virtual bool TypeStruct::isAssignable()':
mtype.c:7761: warning: 'offset' may be used uninitialized in this function
expression.c: In function 'bool arrayExpressionToCommonType(Scope*, Expressions*, Type**)':
expression.c:1119: warning: 'j0' may be used uninitialized in this function
expression.c:1118: warning: 'e0' may be used uninitialized in this function
doc.c: In member function 'void DocComment::parseSections(const utf8_t*)':
doc.c:1395: warning: 'idstart' may be used uninitialized in this function
template.c: In member function 'virtual void TemplateInstance::semantic3(Scope*)':
template.c:7373: warning: 'oldGaggedErrors' may be used uninitialized in this function
template.c: In member function 'virtual void TemplateInstance::semantic2(Scope*)':
template.c:7314: warning: 'oldGaggedErrors' may be used uninitialized in this function
mtype.c: In member function 'virtual MATCH TypeStruct::implicitConvTo(Type*)':
mtype.c:7827: warning: 'offset' may be used uninitialized in this function
clone.c: In function 'FuncDeclaration* hasIdentityOpEquals(AggregateDeclaration*, Scope*)':
clone.c:402: warning: 'tthis' may be used uninitialized in this function
interpret.c: In member function 'Expression* Interpreter::assignToLvalue(BinExp*, Expression*, Expression*)':
interpret.c:3675: warning: 'payload' may be used uninitialized in this function
interpret.c: In function 'Expression* foreachApplyUtf(InterState*, Expression*, Expression*, bool)':
interpret.c:6311: warning: 'eresult' may be used uninitialized in this function

[yebblies]

Auto-merge toggled on