Add missing Unit::isDiplomat

Fixes #1324

docs/changelog.txt

@@ -37,6 +37,9 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 ================================================================================
 # Future
 
+## Fixes
+- `fix/dead-units`: Fixed script trying to use missing isDiplomat function
+
 # 0.44.11-alpha1
 
 ## Structures

library/LuaApi.cpp

@@ -1626,6 +1626,7 @@ static const LuaWrapper::FunctionReg dfhack_units_module[] = {
     WRAPM(Units, isMale),
     WRAPM(Units, isFemale),
     WRAPM(Units, isMerchant),
+    WRAPM(Units, isDiplomat),
     WRAPM(Units, isForest),
     WRAPM(Units, isMarkedForSlaughter),
     WRAPM(Units, isTame),

library/include/modules/Units.h

@@ -139,6 +139,7 @@ DFHACK_EXPORT bool isTamable(df::unit* unit);
 DFHACK_EXPORT bool isMale(df::unit* unit);
 DFHACK_EXPORT bool isFemale(df::unit* unit);
 DFHACK_EXPORT bool isMerchant(df::unit* unit);
+DFHACK_EXPORT bool isDiplomat(df::unit* unit);
 DFHACK_EXPORT bool isForest(df::unit* unit);
 DFHACK_EXPORT bool isMarkedForSlaughter(df::unit* unit);
 DFHACK_EXPORT bool isTame(df::unit* unit);

library/modules/Units.cpp

@@ -1476,6 +1476,13 @@ bool Units::isMerchant(df::unit* unit)
     return unit->flags1.bits.merchant == 1;
 }
 
+bool Units::isDiplomat(df::unit* unit)
+{
+    CHECK_NULL_POINTER(unit);
+
+    return unit->flags1.bits.diplomat == 1;
+}
+
 bool Units::isForest(df::unit* unit)
 {
     CHECK_NULL_POINTER(unit);