Make a separate win32 debug DLL along with the non-debug version:

Currently, src/interfaces/libpq/win32.mak builds a statically-linked
library "libpq.lib", a debug dll "libpq.dll", import library for the
debug dll "libpqdll.lib", a release dll "libpq.dll", import library for
the release dll "libpqdll.lib".  To avoid naming clashes, I would make
the debug dll and import libraries "libpqd.dll" and "libpqddll.lib".

Basically, the debug build uses the cl flags: "/MDd /D _DEBUG", and the
release build uses the cl flags "/MD /D NDEBUG".  Usually the debug
build has a "D" suffix on the file name, so for example:

libpqd.dll     libpq, debug build
libpqd.lib     libpq, debug build, import library
libpq.dll      libpq, release build
libpq.lib      libpq, release build, import library

David Turner

src/interfaces/libpq/libpqddll.def

+; DEF file for MS VC++
+LIBRARY LIBPQD
+DESCRIPTION "PostgreSQL Client Library"
+EXPORTS
+    PQconnectdb             @ 1
+    PQsetdbLogin            @ 2
+    PQconndefaults          @ 3
+    PQfinish                @ 4
+    PQreset                 @ 5
+    PQrequestCancel         @ 6
+    PQdb                    @ 7
+    PQuser                  @ 8
+    PQpass                  @ 9
+    PQhost                  @ 10
+    PQport                  @ 11
+    PQtty                   @ 12
+    PQoptions               @ 13
+    PQstatus                @ 14
+    PQerrorMessage          @ 15
+    PQsocket                @ 16
+    PQbackendPID            @ 17
+    PQtrace                 @ 18
+    PQuntrace               @ 19
+    PQsetNoticeProcessor    @ 20
+    PQexec                  @ 21
+    PQnotifies              @ 22
+    PQsendQuery             @ 23
+    PQgetResult             @ 24
+    PQisBusy                @ 25
+    PQconsumeInput          @ 26
+    PQgetline               @ 27
+    PQputline               @ 28
+    PQgetlineAsync          @ 29
+    PQputnbytes             @ 30
+    PQendcopy               @ 31
+    PQfn                    @ 32
+    PQresultStatus          @ 33
+    PQntuples               @ 34
+    PQnfields               @ 35
+    PQbinaryTuples          @ 36
+    PQfname                 @ 37
+    PQfnumber               @ 38
+    PQftype                 @ 39
+    PQfsize                 @ 40
+    PQfmod                  @ 41
+    PQcmdStatus             @ 42
+    PQoidStatus             @ 43
+    PQcmdTuples             @ 44
+    PQgetvalue              @ 45
+    PQgetlength             @ 46
+    PQgetisnull             @ 47
+    PQclear                 @ 48
+    PQmakeEmptyPGresult     @ 49
+    PQprint                 @ 50
+    PQdisplayTuples         @ 51
+    PQprintTuples           @ 52
+    lo_open                 @ 53
+    lo_close                @ 54
+    lo_read                 @ 55
+    lo_write                @ 56
+    lo_lseek                @ 57
+    lo_creat                @ 58
+    lo_tell                 @ 59
+    lo_unlink               @ 60
+    lo_import               @ 61
+    lo_export               @ 62
+    pgresStatus             @ 63
+    PQmblen                 @ 64
+    PQresultErrorMessage    @ 65
+    PQresStatus             @ 66
+    termPQExpBuffer         @ 67
+    appendPQExpBufferChar   @ 68
+    initPQExpBuffer         @ 69
+    resetPQExpBuffer        @ 70
+    PQoidValue              @ 71
+    PQclientEncoding        @ 72
+    PQenv2encoding          @ 73
+    appendBinaryPQExpBuffer @ 74
+    appendPQExpBufferStr    @ 75
+    destroyPQExpBuffer      @ 76
+    createPQExpBuffer       @ 77
+    PQconninfoFree          @ 78
+    PQconnectPoll           @ 79
+    PQconnectStart          @ 80
+    PQflush                 @ 81
+    PQisnonblocking         @ 82
+    PQresetPoll             @ 83
+    PQresetStart            @ 84
+    PQsetClientEncoding     @ 85
+    PQsetnonblocking        @ 86
+    PQfreeNotify            @ 87
+    PQescapeString          @ 88
+    PQescapeBytea           @ 89
+    printfPQExpBuffer       @ 90
+    appendPQExpBuffer       @ 91
+    pg_encoding_to_char     @ 92
+    pg_utf_mblen            @ 93
+    PQunescapeBytea         @ 94
+    PQfreemem               @ 95
+    PQtransactionStatus     @ 96
+    PQparameterStatus       @ 97
+    PQprotocolVersion       @ 98
+    PQsetErrorVerbosity     @ 99
+    PQsetNoticeReceiver     @ 100
+    PQexecParams            @ 101
+    PQsendQueryParams       @ 102
+    PQputCopyData           @ 103
+    PQputCopyEnd            @ 104
+    PQgetCopyData           @ 105
+    PQresultErrorField      @ 106
+    PQftable                @ 107
+    PQftablecol             @ 108
+    PQfformat               @ 109
+    PQexecPrepared          @ 110
+    PQsendQueryPrepared     @ 111

src/interfaces/libpq/win32.mak

 # Makefile for Microsoft Visual C++ 5.0 (or compat)
 
-# Will build a Win32 static library libpq.lib
-#        and a Win32 dynamic library libpq.dll with import library libpqdll.lib
+# Will build a Win32 static library libpq(d).lib
+#        and a Win32 dynamic library libpq(d).dll with import library libpq(d)dll.lib
 # USE_SSL=1 will compile with OpenSSL
 # DEBUG=1 compiles with debugging symbols
 
@@ -10,13 +10,15 @@
 !MESSAGE
 
 !IFDEF DEBUG
-OPT=/Od /Zi
+OPT=/Od /Zi /MDd
 LOPT=/debug
 DEBUGDEF=/D _DEBUG
+OUTFILENAME=libpqd
 !ELSE
-OPT=/O2
+OPT=/O2 /MD
 LOPT=
 DEBUGDEF=/D NDEBUG
+OUTFILENAME=libpq
 !ENDIF
 
 !IF "$(OS)" == "Windows_NT"
@@ -39,7 +41,7 @@ CPP_OBJS=.\Release/
 !ENDIF
 
 
-ALL : "$(OUTDIR)\libpq.lib" "$(OUTDIR)\libpq.dll" 
+ALL : "$(OUTDIR)\$(OUTFILENAME).lib" "$(OUTDIR)\$(OUTFILENAME).dll" 
 
 CLEAN :
 	-@erase "$(INTDIR)\getaddrinfo.obj"
@@ -62,20 +64,20 @@ CLEAN :
 	-@erase "$(INTDIR)\pqexpbuffer.obj"
 	-@erase "$(OUTDIR)\libpqdll.obj"
 	-@erase "$(OUTDIR)\win32.obj"
-	-@erase "$(OUTDIR)\libpq.lib"
-	-@erase "$(OUTDIR)\libpq.dll"
+	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
+	-@erase "$(OUTDIR)\$(OUTFILENAME).dll"
 	-@erase "$(OUTDIR)\libpq.res"
 	-@erase "*.pch"
 	-@erase "$(OUTDIR)\libpq.pch"
-	-@erase "$(OUTDIR)\libpqdll.exp"
-	-@erase "$(OUTDIR)\libpqdll.lib"
+	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.exp"
+	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
 	-@erase "$(INTDIR)\wchar.obj"
 	-@erase "$(INTDIR)\encnames.obj"
 
 "$(OUTDIR)" :
     if not exist "$(OUTDIR)/$(NULL)" mkdir "$(OUTDIR)"
 
-CPP_PROJ=/nologo /MD /W3 /GX $(OPT) /I "..\..\include" /D "FRONTEND" $(DEBUGDEF) /D\
+CPP_PROJ=/nologo /W3 /GX $(OPT) /I "..\..\include" /D "FRONTEND" $(DEBUGDEF) /D\
  "WIN32" /D "_WINDOWS" /Fp"$(INTDIR)\libpq.pch" /YX\
  /Fo"$(INTDIR)\\" /Fd"$(INTDIR)\\" /FD /c  /D "HAVE_VSNPRINTF" /D "HAVE_STRDUP"
 
@@ -87,7 +89,7 @@ SSL_LIBS=ssleay32.lib libeay32.lib gdi32.lib
 CPP_SBRS=.
 
 LIB32=link.exe -lib
-LIB32_FLAGS=$(LOPT) /nologo /out:"$(OUTDIR)\libpq.lib" 
+LIB32_FLAGS=$(LOPT) /nologo /out:"$(OUTDIR)\$(OUTFILENAME).lib" 
 LIB32_OBJS= \
 	"$(INTDIR)\win32.obj" \
 	"$(INTDIR)\getaddrinfo.obj" \
@@ -117,15 +119,15 @@ RSC_PROJ=/l 0x409 /fo"$(INTDIR)\libpq.res"
 LINK32=link.exe
 LINK32_FLAGS=kernel32.lib user32.lib advapi32.lib wsock32.lib $(SSL_LIBS)  \
  /nologo /subsystem:windows /dll $(LOPT) /incremental:no\
- /pdb:"$(OUTDIR)\libpqdll.pdb" /machine:I386 /out:"$(OUTDIR)\libpq.dll"\
- /implib:"$(OUTDIR)\libpqdll.lib"  /def:libpqdll.def
+ /pdb:"$(OUTDIR)\libpqdll.pdb" /machine:I386 /out:"$(OUTDIR)\$(OUTFILENAME).dll"\
+ /implib:"$(OUTDIR)\$(OUTFILENAME)dll.lib"  /def:$(OUTFILENAME)dll.def
 LINK32_OBJS= \
 	"$(INTDIR)\libpqdll.obj" \
-	"$(OUTDIR)\libpq.lib" \
+	"$(OUTDIR)\$(OUTFILENAME).lib" \
 	"$(OUTDIR)\libpq.res"
 
 
-"$(OUTDIR)\libpq.lib" : "$(OUTDIR)" $(DEF_FILE) $(LIB32_OBJS)
+"$(OUTDIR)\$(OUTFILENAME).lib" : "$(OUTDIR)" $(DEF_FILE) $(LIB32_OBJS)
     $(LIB32) @<<
   $(LIB32_FLAGS) $(DEF_FLAGS) $(LIB32_OBJS)
 <<
@@ -134,7 +136,7 @@ LINK32_OBJS= \
     $(RSC) $(RSC_PROJ) libpq.rc
 
 
-"$(OUTDIR)\libpq.dll" : "$(OUTDIR)" "$(OUTDIR)\libpqdll.obj" "$(INTDIR)\libpqdll.obj" "$(INTDIR)\libpq.res"
+"$(OUTDIR)\$(OUTFILENAME).dll" : "$(OUTDIR)" "$(OUTDIR)\libpqdll.obj" "$(INTDIR)\libpqdll.obj" "$(INTDIR)\libpq.res"
     $(LINK32) @<<
   $(LINK32_FLAGS) $(LINK32_OBJS)
 <<