boost: install DLLs to bin/

Fixes #375.
See   #393.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>

src/boost.mk

@@ -45,6 +45,8 @@ define $(PKG)_BUILD
         -sEXPAT_LIBPATH='$(PREFIX)/$(TARGET)/lib' \
         stage install
 
+    mv -fv $(PREFIX)/$(TARGET)/lib/libboost_*.dll '$(PREFIX)/$(TARGET)/bin/'
+
     '$(TARGET)-g++' \
         -W -Wall -Werror -ansi -U__STRICT_ANSI__ -pedantic \
         '$(2).cpp' -o '$(PREFIX)/$(TARGET)/bin/test-boost.exe' \