Unresolved externals in release mode

My C++ / Fortran mixed language app builds fine in Debug mode, but in Release mode I get the following link errors. 

1>libirc.lib(irc_msg_support.obj) : error LNK2001: unresolved external symbol __imp__LoadLibraryA@4
1>libirc.lib(irc_msg_support.obj) : error LNK2001: unresolved external symbol __imp__GetThreadLocale@0
1>libirc.lib(intel_lib_vs_wrappers_init.obj) : error LNK2001: unresolved external symbol __imp__LoadLibraryExA@12
1>libirc.lib(intel_lib_vs_wrappers_init.obj) : error LNK2001: unresolved external symbol __imp__GetModuleHandleExA@12
1>libirc.lib(intel_lib_vs_wrappers_init.obj) : error LNK2001: unresolved external symbol __imp__GetEnvironmentVariableA@12
1>C:\Users\otakiej\Documents\Subversion\OPT_trunk\Windows10\OPT\Release\OPT\OPT.exe : fatal error LNK1120: 5 unresolved externals

I've compared the compiler and linker settings between the debug and release builds and they seem equivalent.  I'm using VS 2015 and Intel® Parallel Studio XE 2016 Composer Edition for Fortran Windows* Integration for Microsoft Visual Studio* 2015, Version 16.0.0046.14.  Linker output with /verbose:lib is attached.  Please help.