Installation error on some rhub platforms

[kaskr]

Fedora Linux, R-devel, clang, gfortran

#> Error: package or namespace load failed for ‘RTMB’ in dyn.load(file, DLLpath = DLLpath, ...):

[ 994](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-342beb90bda25eb546e300fdd3ee3513#L994)#> unable to load shared object '/home/docker/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so':

[ 995](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-342beb90bda25eb546e300fdd3ee3513#L995)#> /home/docker/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so: undefined symbol: _ZN18objective_functionIN5TMBad6global6ad_augEEclEv

[ 996](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-342beb90bda25eb546e300fdd3ee3513#L996)#> Error: loading failed

macOS 10.13.6 High Sierra, R-release, brew

> Error: package or namespace load failed for ‘RTMB’ in dyn.load(file, DLLpath = DLLpath, ...):

[ 224](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L224)#> unable to load shared object '/Users/userxnrPYxjy/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so':

[ 225](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L225)#> dlopen(/Users/userxnrPYxjy/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so, 6): Symbol not found: __ZN18objective_functionIN5TMBad6global6ad_augEEclEv

[ 226](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L226)#> Referenced from: /Users/userxnrPYxjy/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so

[ 227](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L227)#> Expected in: flat namespace

[ 228](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L228)#> in /Users/userxnrPYxjy/R/00LOCK-RTMB/00new/RTMB/libs/RTMB.so

[ 229](https://builder.r-hub.io/status/RTMB_1.0.tar.gz-0a749f7d91dc53a6d92dc7b2cfdc3b8e#L229)#> Error: loading failed