K 10
svn:author
V 6
pkubaj
K 8
svn:date
V 27
2020-07-19T17:39:36.748762Z
K 7
svn:log
V 204
MFH: r542589

graphics/dspdfviewer: fix build on GCC architectures

To build with Qt5, use C++11 compiler.

Hide Clang-only flags behind .if and add one for GCC.

Approved by:	portmgr (fix build blanket)

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