Use BOOST_FALLTHROUGH in external code

...in preparation of enabling Clang's -Wimplicit-fallthrough

Change-Id: If64f9b18591b3cd2528adc6c2d6011d509d4afcd

external/boost/UnpackedTarball_boost.mk

@@ -84,6 +84,8 @@ boost_patches += boost_1_60_0.undef.warning.patch
 boost_patches += boost.wdeprecated-auto_ptr.patch.0
 boost_patches += boost_1_60_0.android.undef.warning.patch
 
+boost_patches += fallthrough.patch.0
+
 $(eval $(call gb_UnpackedTarball_UnpackedTarball,boost))
 
 $(eval $(call gb_UnpackedTarball_set_tarball,boost,$(BOOST_TARBALL)))

external/boost/fallthrough.patch.0

@@ -0,0 +1,26 @@
+--- boost/format/parsing.hpp
++++ boost/format/parsing.hpp
+@@ -267,6 +267,7 @@
+         switch ( wrap_narrow(fac, *start, 0) ) {
+         case 'X':
+             fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
++            BOOST_FALLTHROUGH;
+         case 'p': // pointer => set hex.
+         case 'x':
+             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
+@@ -280,6 +281,7 @@
+ 
+         case 'E':
+             fpar->fmtstate_.flags_ |=  std::ios_base::uppercase;
++            BOOST_FALLTHROUGH;
+         case 'e':
+             fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
+             fpar->fmtstate_.flags_ |=  std::ios_base::scientific;
+@@ -291,6 +293,7 @@
+         case 'f':
+             fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
+             fpar->fmtstate_.flags_ |=  std::ios_base::fixed;
++            BOOST_FALLTHROUGH;
+         case 'u':
+         case 'd':
+         case 'i':

mysqlc/source/mysqlc_preparedstatement.cxx

@@ -564,8 +564,8 @@ void SAL_CALL OPreparedStatement::setObjectWithInfo(sal_Int32 _parameterIndex, c
             setDouble( _parameterIndex, nValue );
             break;
         }
+        BOOST_FALLTHROUGH;
     }
-    // run through
 
     case DataType::CHAR:
     case DataType::VARCHAR:
@@ -591,8 +591,8 @@ void SAL_CALL OPreparedStatement::setObjectWithInfo(sal_Int32 _parameterIndex, c
             setFloat(_parameterIndex,nValue);
             break;
         }
+        BOOST_FALLTHROUGH;
     }
-    // run through if we couldn't set a float value
 
     case DataType::DOUBLE:
     {