`GetProcAddress` in `DllMain` is problematic (causes deadlocks)

[topolarity]

These lookups (introduced in #114):

libblastrampoline/src/libblastrampoline.c

Lines 493 to 499 in 4cca50a

	for (symbol_idx=0; exported_func_names[symbol_idx] != NULL; ++symbol_idx) {
	exported_func32[symbol_idx] = lookup_self_symbol(exported_func_names[symbol_idx]);
	// Look up this symbol in the given library, if it is a valid symbol, set it!
	build_symbol_name(symbol_name, exported_func_names[symbol_idx], "64_");
	exported_func64[symbol_idx] = lookup_self_symbol(symbol_name);
	}

can deadlock in combination with a parallel dbghelp!SymRefreshModuleList() call (and probably much more).

This leads to hangs in downstream CI (JuliaLang/julia#59650 (comment)) if Profile uses dbghelp concurrently while LBT is being (lazily) loaded.

According to @vtjnash, it is not legal to perform a GetProcAddress inside DllMain on Windows.

[IanButterworth]

Claude's guess for consideration #164